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The increasing demands in modern combustion engines for low emissions and low fuel consumption improved methods for the cycle of combustion. The Beare Heads is a recent 6-hour version of the Beare Heads, recognized also as Malcolm Beare model. Beare Heads uses pistons and harbours such as a 2-hour motor and replacements for the overlap valve system of 4-hour motors. The four-stroke engine, block as well as shaft remain intact. The six-time engine was a mix of two-hit and four-hit technologies. Six Stroke is a six-stroke engine that uses two energy strokes. The six-time engine including external combustion as well as internal dual stream is the same as the real interior combustion engine, according to its mechanical design. Air heating system as well as a combustion chambers, each separate of the cylinder, are two extra chambers throughout the thermodynamic cycles. The six-stroke is heat efficient, since the power pulse pressure changes are larger than for the injection process as well as compression strokes. The major benefits of six-stroke engines included lowering fuel consumption by 40 percent, reducing emissions, versatility for multi-fuel service by 2 power strokes over the six-stroke cycles.

Thermodynamic calculation is the theoretical basis for the study of initiation and detonation, as well as the prerequisite for forecasting the detonation performance of unknown explosives. Based on the VLWR(Virial-Wu) thermodynamic code, this paper introduced the universal solid equation of state (EOS) VINET. In order to truly reflect the compressibility of nanocarbon under the extremely high-temperature and high-pressure environment in detonation, an SVM (support vector machine) was utilized to optimize the input parameters of carbon. The detonation performance of several explosives with different densities was calculated by the optimized universal EOS, and the results show that the thermodynamic code coupled with the universal solid EOS VINET can predict the detonation performance parameters of explosives well. To investigate the application of the thermodynamic code with the improved VINET EOS in the working capacity of explosives, the interrelationship between pressure P-particle velocity u and pressure P-volume V were computed for the detonation products of TNT and HMX-based PBX (HMX: binder: insensitive agent = 95:4.3:0.7) in the CJ isentropic state. A universal curve proposed by Cooper was used to compared the computed isentropic state, where the ratio of pressure to CJ state were plotted against the ratio of velocity to CJ state. The parameters of the JWL(Jones-Wilkins-Lee) EOS for detonation products were obtained by fitting the P–V curve. The cylinder tests of TNT and HMX-based PBX were numerically simulated using the LS-DYNA, it is verified that, within a certain range, the improved algorithm has superiority in describing the working capacity of explosives.

Dual-cylinder driving columns of a hydraulic support are required to be synchronous, with the purpose of guaranteeing the support balance and providing the roof an enough force. In addition, pipelines connecting cylinders with electro-hydraulic servo-valve have a significance influence on synchronization. Taking the length of pipelines into account, the mathematical model of a dual-cylinder driven hydraulic support is built, and the displacement–force coupling characteristic caused by the shared pump is tackled by a decoupling compensator. Following that, an adaptive sliding-mode synchro-position control strategy (ASSC) is designed based on an improved sliding mode reaching law and an adaptive law is developed to restrain the uncertainties resulted from the sub-system after decoupling. The experimental results obtained from the joint simulation platform and practical system show that the proposed controller can effectively reduce the synchronization error between two column positions and has better control performance than the PI and fuzzy PID controllers.

Despite the extensive research already done on laminar flows with porous boundaries, polar flows bounded by cylinders have not yet been studied. This paper investigates the polar laminar flow for an incompressible fluid located in a porous annular pipe and driven by suction-injection at the walls. The fluid being confined between the cylinders with zero axial velocity, it is proven that the flow takes place in the polar plane with conservation of mass if an incoming flow exists in the same plane to compensate the mass of fluid extorted by suction. So, one of the cylinders undergoes the suction, and the other the injection. Suitable boundary conditions for both cylinders are then found. The problem depends on the Reynolds number, the pipe gap ratio, and the pore density and surface ratios. The method of solution utilizes the shooting technique including the Runge-Kutta and Newton-Raphson algorithms. Radial flows are found as a possible solution. When the flow is not radial, the patterns of the acceptable streamlines highlight a particular zone in which the fluid is at rest, bounded by two singular streamlines and the downstream cylinder. The flow velocity is determined. Physical understandings of the flow are derived.

The cyclone separatoris an important separation device. This paper presents a new type of embedded two-stage cyclone, which includes a 2nd-stage cyclone (internal traditional cyclone) with multiple inlets and a 1st-stage cyclone (outer cylinder) that unifies the 2nd-stage cyclone inlets into one inlet. The Taguchi experimental method was used to studythe two-stage cyclone separator's inlet area on its performance. Studies have shown that the increase of the 1st-stage cyclone inlet area and the increase in the number of 2nd-stage cyclone inlets (N) positively affect reducing the pressure drop and a negative effect on efficiency. It is recommended to use 2S (the original 1st-stage cyclone inlet area) of the 1st-stage cyclone inlet area and 2N of the 2nd-stage cyclone inlets when separating fine particles. Compared with a traditional cyclone, the pressure drop is reduced by 1303 Pa, the mass separation efficiency (Eq) is increased by 0.56%, and the number separation efficiency (En) is increased by 2.05%. When separating larger particles, it is recommended to use 2S of the 1st-stage cyclone inlet area and 4N of the 2nd-stage cyclone inlets. Compared with a traditional cyclone, although En decreases slightly, the pressure drop is reduced by 3055 Pa, and the Eq is increased by 0.56%. The research results provide new insight into the design of the cyclone.

A multiphase, transient, horizontal, Taylor-Couette flow has been investigated numerically. This flow governs thermal performance of self-contained drum motor (SCDM) drive systems. These drive systems are extensively used with conveyor belt systems, employed in many industrial and commercial applications. Thermal performance of the SCDM drive system is governed by heat transfer within multiphase flow of air and oil. This flow is confined within a horizontal annular space between two concentric cylinders. The outer cylinder is the drum. It rotates and rejects heat to the atmosphere. The inner cylinder is the outer surface of the motor. It is stationary and subjected to a constant heat flux. This heat is generated within the electric motor, gearbox, and oil viscous dissipation. Numerical simulations have been carried out using ANSYS-CFX. Transient flow and thermal fields have been investigated, starting from an initial stationary state until a quasi-steady state is reached. The effect of drum rotational speed and oil level on thermal performance of the SCDM drive system has been investigated. The study covers a range of rotational speeds from 0 to 150 rpm, oil level from 0%, (i.e., 100% air-filled) to 100%. Numerical results have been validated using experimental data. The optimum oil level has been determined which gives the lowest possible overall maximum SCDM system temperatures. This optimum oil level depends on the drum rotational speed. Results indicated that the 100% oil-filled case does not provide the best thermal performance. The Nusselt number around the inner cylinder has been correlated as a function of rotational Reynolds number and oil level. The developed correlation can be used as a design tool. This tool is to optimize system thermal performance by determining the optimum oil level at a given rotational speed.

Motivated by the need to understand the heat transfer process in permanent mold casting, the heat conduction problem in the casting and the mold is modeled as transient one-dimensional heat flow in a double-layer cylinder with radial interfacial heat flux to emulate the cooling process of the casting. The cylinder is cooled down by dissipating heat to surrounding by convection. Green's function method, which obtained by separation of variables technique, is used to obtain a closed form solution of temperature distribution. The results of the derived analytical expressions are verified with numerical results of finite-element analysis and the published experimental results. The simulations are performed for different casting/mold materials with diversified thermo-physical properties to figure out the relationship between those properties and heat transfer process. The analytical results are justified by their good agreement with both of numerical and experimental results and its time efficiency in computation which offers advantages in potential real-time application to casting process monitoring. The mean absolute percentage error between the obtained temperatures using the developed analytical model and the measured ones was 14.5% and 2.4% for the casting and mold, respectively.

Fluids like hybrid nanofluids have great potential that present exceptional thermal behavior and thermophysical properties as compare to ordinary nanofluids. Hybrid nanofluids are obtained by the mixture of two different nanoparticles in a base fluid. Many scholars stated that hybrid-nanofluids could be replaced by conventional coolants, especially fluids which work at high temperature. Therefore, these kinds of nanofluids are less damaging for environmental impact and also lead to save energy. The main idea of hybrid nanofluids is to develop performance of heat transfer and its advantages has directed to comparatively good hope for its applications. The objective of present article is to examine 3D stagnation point flow of hybrid nanofluid passes along a stretchable heated wavy cylinder under the impact of variable thickness and slip conditions. For this purpose we consider alloy particles of AA7075 + AA7072 and AA7072 which are suspended in methanol liquid. The alloy particles merged in this analysis are entirely manufactured materials as well as possessing higher heat transfer characteristics. Alloy AA7072 is a combination of zinc and aluminum in ratio 1:98 with addition of metals like silicon, copper and ferrous. Similarly, alloy AA7075 is a combination of zinc, aluminum, copper and magnesium in ratio −6, −9, −1 and −3 respectively with addition of metals like silicon, magnesium and ferrous. The scenario of this model is scrutinized mathematically by captivating induced magnetic field with in the domain of thermal boundary layer. Similarity transformations are deployed to change the governing equations into nonlinear ODEs and consequently solved this system through bvp4c solver. The impact of emerging parameters on velocity, induction and energy distributions are examined through graphical depiction. Furthermore, heat transfer rates and drag forces near the boundary are designed numerically in tabular form.

Diesel engines have been using extensively in the automotive industry, power generation systems and marine applications. However, diesel engines release massive nitrogen oxides and soot emissions. Several countries or associations have framed very stringent emission regulations for protecting the environment. In this investigation, the effects of different relative humidity (RH) levels; 40, 50, 60, 70 and 80% (approximately) of intake air on the performance and emission parameters of four-stroke single cylinder turbocharged diesel engine have been analyzed. Load (brake power) ranging from 0.5 to 3 kW are varied. Firstly, the experiments are conducted on a conventional diesel engine (CDE); i.e., naturally aspirated condition, assembled turbocharger with CDE and continued with different RH levels. Further, engine performance analysis such as BSFC and BTE are evaluated, and emissions such as CO, HC, NOx and Soot opacity are measured and compared to CDE. The experimental results revealed that BTE, CO and HC emissions are significantly increased while BSFC, NOx, and Soot emissions are decreased as RH levels increase with particular loads as against CDE. For the maximum operated load at 80% RH level, the maximum reductions in BSFC, NOx and Soot emission are achieved as 4.9%, 30.6% and 58.4% respectively, whereas BTE is enhanced by 4.7%. CO and HC emissions are decreased upto the operated load and increased with an increase in the RH level. The maximum reduction in BSFC and increment in HC and CO emissions are achieved at low load compared to peak load operation with an increase in the RH level.

In the present work, an experimental examination is carried out in a naturally aspirated single cylinder 4-stroke direct injection water cooled compression ignition engine to test the performance of various diesel-apricot kernel biodiesel blends. The objective of the work is to choose the best biodiesel blend proportion that replace pure diesel fuel in CI engine. The selection of such blend is based on the performance and exhaust gases evaluation of the CI engine. The indices considered for the performance evaluation of engine are brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) whereas carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) parameters are examined under tail pipe emissions. The results shown that biodiesel blend of 20% volume proportion of apricot oil in diesel exhibited better performance and emission attributes as compared to other blend proportions.

Laminar cross-flow over a circular cylinder with smooth as well as longitudinally grooved surfaces was investigated numerically for low freestream Reynolds number ranging from 50 to 300. Most of the currently published works on similar flow configurations considered high Reynolds number in the turbulent regime. The computations were performed by the ANSYS Fluent code. The numerical results were validated against the experimental results. The triangular V-shaped, the U-shaped, and Rectangular shaped grooves, with unit aspect ratio; along with the smooth cylinder, are considered. The predicted flow-field for the grooved cylinder cases are analyzed and compared with that for the smooth cylinder. The aerodynamic loads, time-averaged velocities, rms velocity, vorticity, and pressure coefficient plots around the smooth and grooved cylinders were compared to explore the effect of the shape of the grooves on flow dynamics over the cylinder. The flow physics around the cylinder is significantly affected by the shape and size of the grooves, and their circumferential distribution. It is found that the U-grooves significantly decrease the mean drag coefficient (around 13% for Re = 200 and 10% for Re = 300 compared to the smooth cylinder case). The grooves decreased viscous drag significantly (up to 30%) compared to pressure drag. The grooves on the cylinder also delayed the separation and reduced the extent of the recirculation zone in the cylinder wake due to the presence of recirculating flow within the individual grooves. The conclusion is that the properly designed longitudinal grooves on the cylinder in a cross-flow can be used advantageously for reducing aerodynamic loads like drag and lift force in laminar flow as well.

Fossil fuels are used as a fuel for wide range of applications around the world, as per the statistics it is found that the depletion rate of fossil fuel is reducing rapidly. To satisfy the needs of mankind we are in search of an alternative fuel. The present research work is carried out using pongamia pinnata and silkworm oil, on a four-stroke diesel engine as an alternative fuel to find the efficiency of the diesel engine using above specified mixture along with fossil fuel with various blends at different flow rates of engine and calorimeter cooling water. In present investigation the biodiesel is prepared from pongamia oil, and it is blended with silkworm oil. The performance parameters of single cylinder 4 S diesel engine are evaluated.

The Camshaft is a vital part of the Internal Combustion engine of automobiles. It functions as a timing mechanism that controls the opening and closing of the inlet and exhaust valves, as well as the valve overlap that occurs at the TDC of the exhaust stroke. The camshaft is made up of several journals that run on bearings within an engine. The camshaft is bound to rotate with the crankshaft by either a set timing gear, timing belt, or timing chain. As the camshaft drive fails, the valves and piston crowns come into contact, causing extensive internal damage. For high-speed diesel engines (Compression Ignition), power impulses have a greater value than spark-ignition engines in multi-cylinder configurations. In this study, a comparative analysis of an existing automobile camshaft of four-stroke, a four-cylinder Compression Ignition (CI) engine made of Cast Iron was carried out with different compositions of metal matrix composites. For this condition, the outcomes were taken as Von-Mises stresses and displacement values for the static state of the camshaft. The modal analysis (Free vibration) was performed using ANSYS after the static analysis results were obtained. Finally, comparing all the results obtained for different materials, the AlSiC 20% metal matrix composite has been recommended as the most suitable material for the production of camshafts which can replace cast iron because of its similar behavior as to cast iron. This will aid in the development of more precise camshafts, which will be useful for larger displacement engines.

Four-wheeler automotive vehicle is the basic need of people in today’s life all over the world. But the noise coming from the exhaust system is highly affecting the human health. Among all the noise produce in vehicle, exhaust system noise is maximum. Muffler is one such acoustic filter used for reducing this exhaust noise. Hybrid muffler is one type of muffler which combines the properties of both reactive muffler and dissipative muffler and it operates at wide frequency range. In this study an already existing muffler (Reactive type muffler) used in 91bhp, 6000 RPM four-cylinder petrol engine was optimized to hybrid muffler. Aerodynamic and acoustic performance parameters were the main performance parameter and were determined by CFD analysis and acoustic analysis. The existing reactive muffler of the four-cylinder petrol engine could be replaced by the hybrid muffler. Here the mufflers were designed in ANSYS design modular and analyses were performed in ANSYS Fluent and COMSOL software. CFD analysis was performed for the existing muffler and three other newly designed muffler by considering inlet velocity boundary condition at inlet velocity 40 m/s and 80 m/s. It was observed that increase in pressure drop (aerodynamic performance) in model 4, model 3 and model 2 is around 38%, 33.2% and 29% respectively. Again, from acoustic analysis the transmission loss (TL) in model 4 was observed to be 47 dB whereas in other models it was around 20 dB. Further it was observed that the sound pressure level from model 1 at the exit is around 75–78 dB whereas in model 4 it was observed to be around 45–50 dB at the exit. Hence from both the analysis it is concluded that model 4 which is hybrid type muffler is the most optimized muffler.

In order to improve the energy utilization rate, this paper analyzes the flow around the cylinder in the tube-row channel heat exchanger through numerical simulation. Effects of micro-rib structure types (vertical rib and ring rib), number of ribs (N = 0, 4, 6, 8), height of ribs (H = 2, 3, 4 mm), pitch diameter ratio (ST/D = 1.5, 2, 2.5), mass fractions (ω = 0–0.5%) and Reynolds numbers (Re = 514–1205) on the flow and heat transfer characteristics of tube-row channel heat exchangers are analyzed. Results showed that TiO2-H2O nanofluids can improve the comprehensive performance of heat exchanger, and when the mass fraction is 0.4%, the tube-row channel heat exchanger has the best performance. For heat exchangers with different types and structural parameters, the adjustment of the number of ribs, the height of ribs, the ratio of transverse pitch diameter and the use of nanofluids can increase Nusselt numbers by 53.63%, 57.25%, 52.38% and 12.93% at maximum, respectively.

The objective of current numerical analysis is to assess the compression ignition engine performance and emission indices using diesel (B0), spirulina microalgae biodiesel (SMB) blends (SMB20, SMB40, and SMB60) as fuel. The engine chosen for the experimental evaluation and tool validation is 4-stroke solo cylinder of direct injection type diesel engine cooled with water. The numerical assessment is conducted with advanced timing (23.5˚b TDC) of injection and nozzle opening pressure (NOP) 220 bar with half and 100% load condition. The results obtained have shown that SMB20 (20% of spirulina microalgae biodiesel and 80% base fuel) similar results to base fuel (diesel fuel). All spirulina microalgae biodiesel blends reduce brake torque (BT) by 5.7%, indicated efficiency by 0.52% and mechanical efficiency 5.5% at load full condition. Engine exhaust emission results showed that mixed fuel diminishes the oxides of nitrogen (NOX) emission by 4.96% and smoke emission by 11.0% and enhance specific carbon dioxide (CO2) by 3.4% for SMB20 blend at full load condition. The rate of formation of soot (1/deg.) was obtained to be 1.46 for DF, SMB20 by 1.23 and SMB100 by 0.92.

The combustion in Spark Ignition (SI) engine varies from the engine working cycle-by-cycle the ability to predict accurately the pressure allows for a better understanding of the processes that take place in the cylinder The effects of load, compression ratio, and ethanol content on the cycle-by-cycle cylinder pressure variations of a dual spark plug gasoline engine have been investigated experimentally. Cycle-by-cycle cylinder pressure variations were evaluated using coefficient of variation (COV) of maximum cylinder pressure. The results showed that the maximum cylinder pressure increased and corresponding its cycle-by-cycle variations decreased with the increase of load, compression ratio and ethanol content in the blend. Greater variations were observed at lower loads than full load operation of the engine. Highest maximum cylinder pressure and lowest it’s COV were achieved for 20% ethanol by volume in the blend under full load at compression ratio of 10:1. The maximum cylinder pressure crank angle was moved closer to the top dead center as the ethanol fraction in the blend increased. Finally, it can be concluded that the addition of ethanol 20% by volume to the gasoline maintains COV of maximum cylinder pressure at a low level.

The engine is the most important part of an automobile and it is necessary to keep it in working condition for all kinds of temperature conditions. The heat generated inside the combustion chamber needs to be removed to protect the engine from thermal damages and breakdown, in the same instance it is also necessary to make sure that it holds the temperature at an optimal requirement for combustion to take place. The cooling efficiency of the fins is subjected to many factors such as the wind velocity, ambient temperature, fin geometry, material of the fin, and the exposed surface area. Although few parameters cannot be controlled, the engine manufacturer intends to manipulate all possible factors, like fin thickness, fin geometry, and fin orientation to attain a desirable outcome. In this paper numerical simulation of the finned cylinder is presented to improve the heat dissipation rate of an engine. The model is prepared using Autodesk Fusion 360 whereas ANSYS is used to conduct steady-state thermal analysis. Numerical simulations are carried out for two different fin materials: Aluminum alloy 204 and 6061. The effect of fin geometry with varying fin thickness, pitch as well as orientation is also analyzed and a detailed comparison for temperature distribution, total heat flux is presented. Our numerical results show that Aluminum alloy 6061 performed better than the existing configuration with significant improvements in both, heat transfer as well as in power to weight ratio.

With the progression of technology, demands of super alloys have been increased dramatically. One such super alloy is Inconel-718. Although, it is having an extensive application in aerospace industries, steam power plants and oil and gas refineries due to possession of some stringent properties like hot hardness, resistance to wear, high strength. Possession of these rigorous characteristics makes it hard to finish this alloy with the conventional finishing processes almost impossible. So the present work focuses on the predominant role in Industries by giving an edge on surface finishing with more precision and accuracy. To establish the process experimental setup and magnetic tool have been created for chemical assisted magnetic abrasive finishing process to inspect the enhancement in internal roundness of Inconel-718 cylinder. The processing unit has been installed on the lathe machine. Experiments have been performed on Inconel-718 cylinders with 5.7 mm in thickness, 155 mm in length. The experiments have been planned by means of Response surface methodology. Results of the experiments have been analysed with the help of analysis of variance. It has been found that with the operating parameters having specified values like duration of processing-80 mins, Pole work gap-4 mm, and abrasive weight percentage-30%, size of abrasive particle- 40 µm and concentration of Etchant- 700 gm/litre internal roundness improvement percentage for Inconel 718 cylinder is achieved as 42.86%.

In this paper, we report the results for pressures in a full-scale silo obtained from assays performed on a test station using a free-flowing product. Six different types of silo geometry (slenderness and hopper angle) were tested by filling the silo to the height of interest and observing a static phase (10 min) followed by complete discharge. Our results show that discharge flow is not influenced by silo slenderness. The lateral pressure ratio and values obtained for vertical stress in the stored material at the transition were higher than those given in the Eurocode 1, part 4. In addition, the maximum frictional pressures in the cylinder showed peaks that exceeded the standard, as did the maximum normal pressure in the cylinder with maximum slenderness and mass flow (hopper β = 15°).

Liquid desiccant systems (LDS) are promising as they can be driven by renewable energy. Presently, plastic falling film towers are gaining more attention than metallic columns in LDS due to their excellent anti-corrosive characteristics. However, plastics suffer from penurious performance due to their hydrophobic nature. Apart from solid surface wettability, its geometry also plays a vital role in the formation of the continuous thin film over it. In the current experimental work, the dehumidification performance of adiabatic vertical polypropylene (PP) solid circular cylinders is investigated as an alternative to vertical PP plates. Modified circular cylinder surface is prepared following surface modification to overcome hydrophobic nature of the plastic surface. The performance of the circular cylinder surface is compared with the plate surface. It was found that the Plain PP circular cylinder offered 21–200% improvement in dehumidification rate as compared to the Plain PP plate with an average improvement of 55.9%. Similarly, the Modified PP circular cylinder enhanced the dehumidification rate of the Plain PP circular cylinder by 18.2–61% with an average improvement of 31.3%. A new generalized correlation is proposed to predict the effectiveness of adiabatic and non-adiabatic falling film towers by incorporating shear force, enthalpy difference, and moisture transfer potential between liquid desiccant and air along with wetness behavior parameters. The mean effective error of the current correlation is 11.7% for eight datasets. The findings of this study could be useful for designing small capacity low flow falling film tower-based solar hybrid liquid desiccant systems for residential and commercial applications.

The inlet duct length may affect the gas flow field and performance of a cyclone separator with a contracted inlet duct. In this study, a numerical simulation using the Eulerian-Lagrangian approach with a one-way coupling method was conducted to evaluate the gas flow field and separation efficiency of the cyclone separators with contracted inlet ducts of different lengths. The simulation results indicated that increasing the inlet duct length led to higher gas tangential velocity in the cyclone body. The effect of the inlet duct length on gas axial velocity was inferior to that on gas tangential velocity. A longer inlet duct reduced both the pressure drop and the separation efficiency. The reductions of the expansion loss at the inlet of the cylinder and friction loss inside the cyclone body contributed the most reduction of the pressure drop as the inlet duct length increased. Generally, when the inlet duct was 1.5 times longer than the cylinder diameter, the effect of inlet duct length on the gas flow field and performance of a cyclone separator became slight.

The present work discusses an attempt to enhance the mechanical and reciprocal wear response of Al–7Si-0.3 Mg alloy through the addition of 10 wt% SiC as reinforcement and subsequent T6 treatment. Friction and reciprocating wear behavior of both untreated and heat treated functionally graded composites were studied under unlubricated sliding conditions, employing a linear reciprocating pin-on-plate system over a range of applied load (10–50 N) and sliding distance (500–2500 m). Microstructural studies revealed reinforcement particle gradation across the cast thickness for untreated composite with minimal particle clusters whereas, heat treated composite showed the presence of fine α-spheroidised eutectic silicon. The outer layer of heat-treated composite when compared to outer layer of as-cast composite, revealed an 18 % increase in hardness, 70 % increase in tensile strength and 8 % decrease in wear rate. Wear studies confirmed a linear dependency between wear rate and applied load whereas, coefficient of friction displayed fluctuating trends. Wear mechanisms were identified, with worn morphology and EDS analyses in agreement with the results obtained and was correlated with the observed metallurgy and mechanical properties. These composites were identified as potential candidates for applications such as brake drums/rotors, cylinder liners, cylinder blocks and pistons.

In rotary compressors, adding one cylinder to the conventional two in the axial direction without increasing the flow rate and load per cylinder can be expected to be an effective means for further increasing the capacity without deteriorating efficiency and reliability. This paper presents the prototype design with three different specifications for a three-cylinder rotary compressor, their performance measurement results, and their efficiency analysis. To investigate a bending deformation of the crankshaft, we have performed an axis behavior analysis as the elastic body and used the results for the efficiency analysis. Our efficiency analysis finds that the three-cylinder rotary compressor requires a middle bearing between the cylinders to reduce leakage in the compression chamber. The three-cylinder prototype demonstrates a higher COP than two-unit operation of the two-cylinder conventional models in almost the entire refrigeration capacity range and a great advantage in the medium capacity range especially.

This paper presents an FE and theoretical study on bolted ball-cylinder (BBC) joint, which mainly consists of a circular tube welded to a solid hemisphere. As a new type of jointing system for non-purlin grid structures, BBC joints may be subjected to compressive, tensile and bending loads. A non-linear FE model was developed and its reliability was verified by the experimental results from existing literature. For a design purpose, the FE model was improved by removing the additional constraints that needed during the test and modifying the material constitutive model. Failure modes, typical load–displacement relationships and stress distributions were studied based on the FE simulations. Parametrical study was conducted to investigate the influence of key parameters, such as diameter, thickness, height of the circular tube, width and height of the tubular beam, on the structural behaviour of BBC joints under various loading scenarios. Finally, empirical formulas were proposed to predict the ultimate load capacity of BBC joints and the prediction agreed well with the FE results.

The breakage of prestressed steel wires is the main cause of failure in prestressed concrete cylinder pipes (PCCPs). Current finite element models with clustered broken wires (CBW), which either remove all of the broken wire coils or consider the partial loss of prestress through simplified contact interactions, cannot reflect experimental phenomena such as the olive shape formed by wire breakpoints and the distribution of cracks in the concrete core. In this study, spring elements are inserted into the model through Python scripts to transfer the compressive prestress and simulate the breakage and bond-slip of steel wires. Moreover, a cohesive contact interaction is defined to simulate the delamination of the mortar coating. The results show that in the pipe subjected to a water pressure of 1.2 MPa, the number of CBW corresponding to the onset of visible cracks in the mortar, outer core, and inner core, yielding of the cylinder, and pipe failure are 20 (4.17%), 50 (10.42%), 70 (14.58%), 80 (16.67%), and 110 (22.92%), respectively. The number of CBW associated with pipe failure calculated by the proposed model falls between those of the other two current types of models.

The crystallinity index of cellulose decrystallized with a vibration rod mill was well correlated with input energy of the vibration rod mill. In order to predict the energy, rod behavior was simulated by discrete element method (DEM). Decrystallization of cellulose was performed using a vibration rod mill to increase the reactivity. The decrystallization speed increased with an increase in the number of rods and the crystallinity index of cellulose after pulverization can be uniquely identified by the input energy [kWh/kg], which is actual power times pulverization time divided by cellulose mass charged into the vibration rod mill. Therefore, the actual power of the vibration rod mill was calculated using DEM simulation, wherein rods were constructed by connecting spherical particles using the multi-sphere method. The coefficients of friction and restitution were determined based on the movement of the rod in the mill cylinder from the experiments. The power calculated agrees with the actual power. This study suggests that the power of the vibration rod mill can be predicted using DEM and that the crystallinity index can be predicted without experimentation.

Coal mine methane (CMM) combustion in the porous media burner (PMB) of boiler system contributes to the simultaneous production of hydrogen and heat, and the hydrogen can be used as the main raw materials for solid oxide fuel cell (SOFC). In this study, the double-layer burners were built by filling the downstream with the hollow cylinders of different sizes and pore numbers due to the high porosity of hollow-structure units compared with the common packed bed of pellets. The distributions of temperature, species concentration and reforming efficiency were obtained on the consideration of operating condition and preheating temperature. Results shows that the reforming efficiency of the 10-6-10 mm cylinder burner was optimal in all one-pore cylinder burners with the highest concentration of 12.3% (H2) and 8.8% (CO). As for the packed bed of 8 mm cylinders, the four-pore cylinder burner showed the highest peak temperature and maximum yields of hydrogen. With the increasing of preheating temperature, the stabilization time of the flame propagating decreased. Moreover, the peak temperature and reforming efficiency increased with the increasing of the inlet velocity and the largest efficiency of 54.2% appeared at the velocity of 18 cm/s in the 10 mm cylinder burner.

Although studies have reported the accuracy of 3D-printed dental casts, studies addressing cast distortion throughout the complete-arch range are lacking.The purpose of this in vitro study was to evaluate the dimensional accuracy of different areas in complete-arch casts made with various 3D printing methods.A computer-aided design (CAD) reference cast was modified from a mandibular cast by adding 6 cylinders in the canine, second premolar, and second molar locations and 3 spheres to define a coordinate system. A total of 50 casts were printed with 5 group materials, which included fused deposition modeling (FDM), digital light processing (DLP1 and DLP2), photopolymer jetting (Polyjet), and stereolithography (SLA). After scanning the 3D printed casts, the overall consistency was examined by superimposing them on the CAD reference cast and measuring the deviations. For dimensional accuracy, cylinder top coordinates were extracted from each printed cast, and X-, Y-, and Z-deviations and the 3D deviation were calculated by subtracting the coordinates of the CAD reference cast from the cast values. Statistical analyses were conducted by the Kruskal-Wallis test and the Mann-Whitney post hoc test (α=.05). Surface characteristics were examined with photographs and scanning electron micrographs.FDM showed more systemic deviations than DLP, Polyjet, and SLA from superimposing analysis (P.01). In the X-axis, FDM and DLP showed contraction, while Polyjet and SLA showed expansion (P.01). In the Y-axis, FDM showed forward deviations on the right side and DLP showed contraction (P.01). Three-dimensional deviation at each cylinder location was lowest in the left canine region, and deviations increased with distance from this site in all groups. The qualitative features of casts varied among 3D printers in terms of shape, surface smoothness, and edge sharpness.FDM and DLP casts tended to contract, whereas casts in the Polyjet and SLA groups expanded buccolingually and anterioposteriorly. Vertically, deviations were smaller than those in the other directions.

A numerical investigation is carried out for the different orientations of a circular cylinder where the upstream cylinder moves with varying angles α = 0˚, 30˚, 45˚, 60˚, 90˚ with respect to the downstream cylinder in a fixed position at a gap ratio (L/D) of 3 where L is the distance from centre to centre between cylinders and D is the diameter of the cylinder. Reynolds number (Re), is based on cylinder diameter, is kept constant at 200 for all the cases with air as the working medium. The vortex shedding formation is analysed when the vortices from the upwind cylinder interact with the downwind cylinder and give impressive flow patterns. It is observed that the drag and lift coefficients increase for both the cylinders with change in angular position. Strouhal number is calculated with the help of Fast Fourier transformation (FFT) of vorticity magnitude and evaluated for each case. It is observed that the effect of upwind cylinder on downwind cylinder is significant for α = 30˚, 45˚, 60˚ orientation cases and vortex shedding frequency increases for these cases. Further, the investigation is extending on the laminar forced convection heat transfer performance and variation of Nusselt number for the cylinders. Maximum heat transfer is observed for the downwind cylinder at α = 45˚. In contrast, the local Nusselt number does not vary much for the cylinders except for the downwind cylinder at α = 0˚.

Literature includes several empirical models to predict shear capacity of steel fiber-reinforced concrete (SFRC) beams. However, some of these models were calibrated based on small database of experiments or include data for beams failed in flexure. This study utilizes a database of 241 tests of SFRC beams failed in shear along with gene expression programming (GEP) to establish more accurate and reliable predictions. Independent variables included in the GEP were fiber factor, longitudinal reinforcement ratio, concrete cylinder compressive strength, and shear span-to-depth ratio. The model provides an average ratio (vtest/vpredicted) of 1.00, a coefficient of variation of 24%, and a root mean square error of 1.33 MPa. The proposed model provides a higher accuracy when compared to existing models in the literature. The study also presents a reliability analysis study to evaluate the safety level embedded in the proposed model. By comparing the safety level of the proposed model to the safety level in reinforced concrete beams without shear reinforcement according to ACI 318-19 equation, a strength reduction factor of 0.5 instead of 0.75 is proposed to achieve consistent safety level with conventional reinforced concrete. Additionally, a varying strength reduction factor with respect to shear span-to-depth is also proposed.

A fatigue life prediction method is developed for the high-pressure hydrogen storage vessel based on theoretical research and experimental verification. Firstly, the finite element model of vessel was built considering wound angle of head, thickness and number of the composite layer, then simulation was performed. The optimum range of autofrettage pressure was obtained by FEA with consideration of the DOT-CFFC and CGH2R standards. The influence of autofrettage pressure, metal liner thickness, and fiber thickness on vessel fatigue life was discussed under internal pressure cyclic load. Finally, the experimental verification was carried out. It was found that fatigue failure first occurred in middle cylinder. The experiment results agree well with theory analysis. Their average error is 6.33%.

Coaxial one-side resistance spot welding (COS-RSW) is an advanced technique for joining CFRP/metal dissimilar materials. In the present work, a three-dimensional model was developed based upon an in-house finite element code JWRIAN-SPOT to simulate the multi-physical process of the COS-RSW. The thermal cycle and joining strength of COS-RSW joints with different welding parameters were measured experimentally. The sensitivity of material properties of electrode couple and component of accumulated heat generation were discussed in detail. The predicted thermal cycles presented a reasonable agreement with measurements, which also explained the influence of welding parameters on temperature field. The joining strength of COS-RSW joints can be evaluated qualitatively via the area of effective molten zone, which reached about 20 MPa with a 4800 A welding current. The column and cylinder electrodes determined the peak value of interface temperature and molten zone area, respectively. The cylinder electrode was suggested to be fabricated by a high resistivity material to generate sufficient Joule heat. Moreover, the SUS304 electrode and its contact zone provided more than 70% of the entire heat generation. The materials of electrode couple should be determined carefully when employing COS-RSW for joining CFRP and other metals.

The effects of particle shape on the thermohydraulic performance of a boehmite nanofluid in a microchannel heat sink (MCHS) with different cross-sections are investigated. This investigation is performed for five nanoparticle shapes (platelet, cylinder, blade, brick, and oblate spheroid) at four Reynolds numbers in the MCHS with four cross-sections (i.e., circular, triangular, hexagonal, and elliptical). The MCHS with triangular microchannels demonstrates the greatest heat transfer coefficient, followed by the MCHSs with elliptical, hexagonal, and circular microchannels, respectively. The best temperature distribution and the lowest thermal resistance are realized for the MCHS with triangular microchannels. Moreover, the MCHS with circular microchannels results in the highest Figure of Merit (FoM), while the MCHS with triangular ones demonstrates the lowest FoM. The nanofluid with platelet particles causes the highest pressure loss, whereas the one with the Os-shaped particles has the lowest pressure loss. For all the nanoparticle shapes and cross-sections, uniformity of temperature distribution (θ) and thermal resistance reduce, while the heat transfer coefficient, pressure drop, and pumping power increase by rising the Reynolds number. Additionally, the colloid with the platelet-shaped particles causes the greatest heat transfer coefficient, pursued by the nanofluids with the cylinder-, blade-, brick-, and Os-shaped particles, respectively.

The dome reinforcement (DR) technology was studied to reduce the amount of carbon fiber of the type IV hydrogen storage vessel in this paper. Firstly, the influence of the angle and thickness of the dome reinforcement part on the stress distribution of the dome section is studied by finite element analysis. Secondly, the weight reduction of carbon fiber composite layer is studied based on the dome reinforcement model. The strain-based Hashin progressive damage model is used to predict the burst pressure and burst mode with user-defined material subroutine (UMAT) of ABAQUS. Finally, the dome reinforcement technology is further verified in comparison with non-dome reinforcement by burst tests. The results show that the progressive damage model can effectively represent matrix cracking and fiber fracture, and the predicted burst pressure and mode is consistent with the test results. The fiber stress near the equator of the dome section affects the burst mode, and the smaller the angle of dome reinforcement parts, the better the reinforcing effect, and the dome reinforcement technology can help to improve the fiber damage state at the dome, transfer the maximum stress to the cylinder section of the vessel, and ensure the burst mode to be a safe mode. Also, it can help to reduce the consumption of carbon fiber by up to 5.5% in composite material.

The unique characteristics of the nanosized silver thiocyanate structure motivated the researchers to apply it as an effective agent nanoparticles additive in Diesel/Biodiesel fuel blends. Nanostructure of silver thiocyanate was measured by High resolution transmission electron microscope giving nano diameter between the values of 7.23:7.98 nm. The engine test has been achieved using 200, 400, and 600 ppm nanoparticles of silver thiocyanate additives to the blends of D50B50 (50%diesel & 50% biodiesel by volume). The tested blends are subjecting to a continuous stirring by using a mechanical movement pump to enhance the harmony of the nano-solid inside the blended fuel. During the engine test, the obtained fuel blends are stable and steady and the engine is running smoothly at fixed speeds of 1400 RPM and loads variation. The nanoparticles silver thiocyanate act as an oxygenated contributing catalyst. However, the existence of the extra oxygen inside the engine cylinder participates in reducing the unburned hydrocarbon emissions. The obtained results showed that the 400-ppm nanosized silver thiocyanate comparatively presents a better performance, combustion, and emission with respect to another tested dos. Unburned hydrocarbons and smoke emissions were dramatically reduced by adding the silver thiocyanate nanoparticle, which has working as combustion exciter that enhances the heat release rate process inside the DI-engine cylinder.

In this numerical contribution, hybrid nanofluid flow behavior, thermal characteristics, and entropy generation analysis through a porous enclosure containing three circular cylinders with magnetic field effects were investigated using finite element approach. The cylinders are arranged in horizontal arrangement in the middle of cavity height, and the active hot central cylinder can move along the vertical central axis while other cold cylinders are considered fixed. The cylinders are enclosed by an adiabatic wavy cavity loaded with Cu-Al2O3-water. The results are discussed for the scrutinized parameters e.g., Rayleigh number (Ra), Darcy number (Da), Hartmann number (Ha), relative position of the hot cylinder (δ), and concentration in volume of nanoparticles (ϕ). It was inferred that the thermal-natural convective flow and overall heat transmission were reinforced by boosting Ra and Da, and lowering Ha. Changing the relative position of the hot cylinder has a remarkable effect on nanoliquid flow patterns, convective heat transfer and entropy generation characteristics.

The study of potentially high rated alternative fuel (Methanol) for the IC engines is an exciting topic in the recent research advancement. However, the study of combination of methanol and hydrogen is considered to address both economic and environmental needs. Hydrogen with best combustion characteristics will compensate for the drawbacks of methanol as a fuel. In the present investigation hydrogen enrichment to methanol has shown a significant enhancement in performance and combustion; the overall emission has reduced substantially. The experiments for a different set of trials, including hydrogen enrichment ranging between 5% and 20% with 2.5% increment, the engine is operated with wide-open throttle (WOT) condition for different speeds. The increase in enrichment of hydrogen has shown a rise in BTE, BP, and a reduced BSEC value. The percentage increase in BTE is between 20 and 30%, and an increase in hydrogen beyond 12.5% would affect the volumetric efficiency, and thus performance declines after that. The exhaust emissions have a huge impact on hydrogen enrichment; CO, HC, and CO2 emission are reduced by 30–40%; however, an increase in cylinder temperature due to rapid combustion slightly increases the NOx emission. Thus hydrogen enriched methanol operating at higher compression ratio can improve the overall engine characteristics significantly.

In the piston ring-cylinder system, the surface topography is crucial to their tribological performance, emphasizing the relevance of the surface finishing processes. The present work studied the influence of different finishing processes in the surface roughness parameters of the coated compression piston rings. Three distinct surfaces’ finishing processes were used in the first approach: Option A, B, and C. Options D comprised the variation of different processing parameters. The piston rings with different surface topographies were tribologically evaluated using a tribometer developed explicitly for this industrial evaluation. Regarding the tribological performance, it was concluded that the use of the surface finishing processes fostered a decrease in the coefficient of friction. The surface finishing had also impacted the wear of the piston ring and in the counterbody. An increase in the piston rings’ surface roughness led to a rise in the surface's weight loss.

In the pursuit to improve thermal and fuel efficiencies of internal combustion engines, various engine designs and configurations have been developed over recent years. Since the progress in this field keeps on increasing continuously, the geometrical aspects of combustion chamber and the engine configurations and their effects on the in-cylinder air/fuel mixing, turbulence and fuel combustion are becoming more relevant than ever. Due to this, there lies an impending need for a critical analysis of current in-cylinder flow analysis techniques available, their application on different engine types and the results acquired from the studies. Several new flow measurement technologies have emerged and for the past ten years, a critical analysis of airflow capturing methods within IC engines has not been done despite its great significance. This review presents a short yet a meaningful understanding to the analysis techniques for engine in-cylinder flows during the intake and compression of air and fuel, while bringing out significant findings from individual works, resulting in pointing out the strengths and accuracies of these techniques. In the reflection of reviewed studies, explicit analytical schemes and formulations bearing least errors compared to experimental results, are suggested.

We studied the relationship between pre-chamber jet and main chamber ignition in the pre-chamber combustion (PCC) of an optical engine, fueled with methane and equipped with an active pre-chamber with two rows of orifices. Acetone planar laser-induced fluorescence (PLIF) and OH* chemiluminescence imaging techniques were simultaneously applied to visualize the pre-chamber jet and the reaction zone in the main chamber, respectively. The pre-chamber fueling was constant and the main chamber fueling was increased to form an ultra-lean case and a lean case with global excess air ratios (λ) of 2.3 and 1.8, respectively. Results indicate that a higher pressure difference between pre-chamber and main chamber ( ▵ P) produces larger pre-chamber jet penetration speed; the maximum pre-chamber jet penetration speed appears at timing around the peak ▵ P. Over enrichment of the pre-chamber charge reduces the peak ▵ P and thus does not favor a faster pre-chamber jet discharge. In addition to the main pre-chamber jet, a weaker post jet discharge process is visualized; the former is due to the pre-chamber combustion while the latter due to the ▵ P fluctuation and the cylinder volume expansion. The post pre-chamber jet is accompanied by a post reaction zone in the ultra-lean case (λ=2.3) and there are two unburned regions in the main chamber: one is around the pre-chamber nozzle and the other between the adjacent reaction zones. These two unburned regions are consumed by flame propagation in the lean case (λ=1.8). The weak pre-chamber jet from the upper-row orifice does not produce any distinct reaction zone, indicating that the pre-chamber orifice location and arrangement on the nozzle also matters in the pre-chamber design. The pre-chamber jet penetration length is longer than that of the reaction zone during pre-chamber discharge; the penetration length difference between the pre-chamber jet and reaction zone decreases with increasing main chamber fueling.

Gaseous hydrogen stored in high-pressure cylinder is a proper solution for the application of hydrogen fuel cell buses (HFCB). As far as the on-bus hydrogen storage system (OBHSS) is concerned, the filling of hydrogen gas needs to be finished in an acceptable time, which unavoidably brings the increase of temperature of hydrogen gas in OBHSS. And excessive temperature of hydrogen gas is unfavorable to mechanical properties of wrapping material and even the service life of the storage cylinder, so it is urgent to work out effective strategies on the temperature-rise in the storage cylinder. It is noticed that the studies on the relationship between the temperature-rise and the geometrical parameters of on-bus gaseous hydrogen storage cylinder (OBGHSC), e.g. thickness of liner and fiber/epoxy composite laminate, are still not deep enough. Motivated by this fact, this research is therefore devoted to studying the relationship between the temperature-rises of both hydrogen gas and solid materials in OBGHSC and the geometrical parameters of wrapping material and liner of OBGHSC, and to developing several temperature-rise correlations. To do so, a 2-dimensional (2D) axisymmetric computational fluid dynamics (CFD) model is applied for the simulation of fast filling process and holding process of 70 MPa OBGHSC. The simulation results show that the temperature distribution during the filling is different for different type III storage cylinders, while the highest temperature is always in the head dome junction region for type IV storage cylinders. For the carbon fiber/epoxy composite laminate (CFEC), the temperature varying tendencies are not the same for different type III storage cylinders, while the temperature in type IV storage cylinder decreases with the increase of thickness of CFEC. At last, based on the obtained numerical data, the correlations for highest value of mass-averaged temperature-rise of hydrogen gas and the correlations for maximum temperature-rise of CFEC that account for the effects of dimensionless parameters are proposed. The correlations reveal the relationship between the temperature-rise and the structure of hydrogen storage cylinder and can be used to direct the fast filling process for OBHSS in this research.

Increasing deployment of fuel cell electric vehicles (FCEVs) has led to implementation of hydrogen quality regulations (ISO 14687:2019) to prevent FCEV loss of performance. Hydrogen refuelling stations operators must be able to send representative samples of hydrogen fuel for analysis. Stability of contaminants in sampling vessels needs to be known at ISO 14687:2019 thresholds. A 4-month stability study was carried out on mixtures of ISO 14687 contaminants at amount fractions close to the thresholds in two types of sampling cylinders (SPECTRA-SEAL® and SGS™ aluminium cylinders). SPECTRA-SEAL® cylinder allowed representative sampling of CO, CO2, CH4, C2H6, N2, Ar, He, Cl2CH2, H2O, O2, CH2O2 in hydrogen fuel for 2 months. SGS™ cylinder allowed representative sampling of CO, CO2, CH4, C2H6, N2, Ar, He, Cl2CH2, H2O, O2, H2S for 4 months. Further work is needed to allow representative sampling of ammonia and formaldehyde.

Gas–solid two-phase flow and water vaporization processes tend to have a significant impact on the efficiency of flue gas desulfurization with a powder-particle spouted bed. According to the numerical results obtained in this study, the 2D spouted bed developed a classic three-area flow, and the 3D spouted bed entered into a bubbling-like state. The gas and particles flowed in the opposite direction at the junction of the cone and cylinder. The water vaporization rate was higher at the junction of the spout area and the annulus area, lower at the center of the spout area, and the lowest in the annulus area of the 3D spouted bed. Furthermore, it was found that a larger gas velocity, a higher liquid temperature, and a lower gas humidity leads to a higher water vaporization process.

A combined experimental and numerical characterization of a Compression Ignition (CI) engine is here presented under Diesel and Waste Vegetable Oil (WVO) fueling at different loads. Main objective is to prove the feasibility of preheated WVO as substitute of Diesel fuel in CI engine for cogeneration purposes without modifying the engine geometry. After a characterization of the WVO physical properties, an appropriate pre-heating system is mounted on the engine injection line in order to reduce viscosity. The in-cylinder pressure analysis reveals no significant differences under both fuelling modes, despite an increased fuel consumption measured for WVO. This last provides higher NOx, CO and CO2 emissions, with a strong reduction (50–80%) of the soot amount. The potential impact of employing WVO is then assessed through a Life Cycle Assessment (LCA) methodology with focus on the fuel production and use stages. A reduction in all the major impact categories is noticed with respect to Diesel fueling. At the same time, a 3D CFD model of the engine is developed and validated. The WVO injection process shows slower spray break-up and evaporation rates due to higher viscosity and density. Despite the higher penetration lengths and increased amount of fuel burnt closer to the cylinder walls, the soot at the exhausts remains low as a consequence of the absence of aromatic compounds and an enhanced oxidation process due to the presence of oxygen atoms in the WVO molecules. This aspect is also responsible of the increased NOx release.

The goal of the present research is to study the impact of a stationary wiper almost touching a revolving zinc solid cylinder on the rate of Cu+2 cementation. Initial Cu+2 ions concentration, speed of rotation, and the effect of the presence and absence of a wiper were investigated. The degree of Cu+2 cementation was stated in relation to the mass transfer coefficient which was valued under diverse circumstances. The present study showed that the mass transfer coefficient accelerates as rotation speed and quantity of Cu+2 increase. The presence of a wiper enhances the degree of Cu+2 cementation by an extent that varies from 1.59 to 64% subject to the operational circumstances. The present mass transfer data have been interrelated by dimensionless equations. The importance of such relationships in the sizing and running of rotating cylinders used for performing diffusion- restricted reactions is underlined.

Currently, most automotive industries use fossil fuels, like diesel fuel, which are harmful for the environment and are known as the main reason for global warming. To reduce the adverse effects of these fuels, scholars have investigated and suggested green fuels like biodiesel. However, further studies should be conducted to improve the functionality of biodiesel fuel in diesel engines. In the current study, three completely distinct biodiesel fuels (namely, B1 with 96 % lauric oil, B2 with 88 % oleic oil, and B3 with 89.5 % ricinoleic oil) were numerically evaluated to carefully investigate the effects of the number of carbon atoms, the O H bond, and viscosity on the performance of a CI engine. First, the predicted in-cylinder pressure, the rate of heat released, and NO emissions were compared to experimental results and an appropriate accord was obtained. For the mentioned biodiesels, the parameters of engine speed, injection angle, piston bowl center depth, and compression ratio were investigated by CFD code under different engine speeds. It was found that changing the piston bowl center depth (PBCD) value from 0.0042 to 0.009 m increased NO and the indicated power by 4% and 3%, respectively, for B1, B2, and B3 biofuels. In addition, when the engine was fueled by Corylus avellana biodiesel, the change in compression ratio from 16 to 24 increased peak pressure and torque by around 77 % and 17 %, respectively. The results showed that the cylinder fueled by high viscosity biodiesel has lower air-fuel mixing. A fuel that has more oxygen atoms in its chemical structure can produce higher NO emissions. Moreover, the injection angle of 150° led to increased fuel consumption rate and indicated power compared to the injection angle of 160°. It was determined that the compression ratio has significant effects on emission and combustion characteristics.

Hydrogen gas stands as a renewable energy fuel for the transportation sector. The hydrogen to air ratio is an essential factor in deciding the combustion and therefore the thermal efficiency of an internal combustion engine. In this study, the mixing of hydrogen and air is considered among the four geometrical configurations. These cases are considered from the simple duct and vortex tube which induces an additional swirl inside a cylinder. The approach of the study involves the meshing and computation of mass, momentum and energy equations by finite volume method. After the convergence of results, mixture ratio is analyzed with the velocity components and vorticity variables. The ratio of hydrogen to air is found to vary between 8 and 35 among the cases considered. The desired ratio could be obtained from the combination of vortex tube and plain duct configurations. Stratification of mixture is found to be significant from the gradient of velocity components in this study.

Dual fuel internal combustion engines (ICEs) using diesel and fuels that are vaporous in normal conditions are collecting consideration for two motives. First is the occasion to achieve diesel-like power density ϕ and fuel conversion efficiency η steady-state, and similar transient performances. Second, is the chance to deliver better than diesel engine-out emissions, for CO2, particulate matter, unburned hydrocarbons, and nitrous oxides. A high-pressure (HP) cryogenic liquid injector is proposed for H2 and applied to a high compression ratio high boost ICE featuring 2 direct injections (DI) injectors per cylinder, 1 diesel, and 1H2. Super-turbocharging (mechanically assisted turbocharging) is employed to make better steady-state performances, especially low-speed high-load, but also high-speed high-load, and transients, principally eliminating the turbo-lag. This work aims at evaluating the benefits of further increasing the injection pressure of the cryogenic hydrogen in a specific dual fuel diesel-hydrogen engine setting. With the proposed 1600 bar injector, this ICE delivers top η>52%, and higher η>40% over most of the speed-load range, with the option to further increase ϕ vs. the baseline diesel working less lean at top loads and adopting mixed premixed-diffusion combustion modes.