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In this research paper, the authors aim to establish a novel algorithm in the finite difference method (FDM). The novel idea is proposed in the mesh generation process, the process to generate random grids. The FDM over a randomly generated grid enables fast convergence and improves the accuracy of the solution for a given problem; it also enhances the quality of precision by minimizing the error. The FDM involves uniform grids, which are commonly used in solving the partial differential equation (PDE) and the fractional partial differential equation. However, it requires a higher number of iterations to reach convergence. In addition, there is still no definite principle for the discretization of the model to generate the mesh. The newly proposed method, which is the SM method, employed randomly generated grids for mesh generation. This method is compared with the uniform grid method to check the validity and potential in minimizing the computational time and error. The comparative study is conducted for the first time by generating meshes of different cell sizes, i.e., 10×10,20×20,30×30,40×4010\times 10,\hspace{.25em}20\times 20,\hspace{.25em}30\times 30,\hspace{.25em}40\times 40 using MATLAB and ANSYS programs. The two-dimensional PDEs are solved over uniform and random grids. A significant reduction in the computational time is also noticed. Thus, this method is recommended to be used in solving the PDEs.

Heat exchangers play a vital important role in industries and processing equipment's. Among them, the double pipe heat exchanger facilitates the exchange of heat between two fluids through surface tubes. This study aimed to investigate various thermal performance parameters of baseline water and Aluminum oxide nanofluid at various volume concentrations and flow rates. The results were compared between baseline water and Aluminum oxide nanofluid using a test rig at the temperature range of 60 °C for industrial applications. The nanofluid sample was prepared by adding very small-sized (20nm) Al2O3 nanoparticles in the baseline water within the range of 0.10% to 0.175% using a standard two step method for the sterilization process. The nanoparticle and baseline water were under set by a hot plate mechanical stirrer for approximately 2 hours to ensure the proper dispersion before the tests, rendering the nanofluid stable for 12 hours. The Laminar-Transition flow double pipe heat exchanger (test rig) operated at flow rates ranging from 1.6×10-5-3.3×10-5 m3/sec (1-2 LPM) within the range of Reynolds number from 1700 to 3400 at volume concentration of 0.10% to 0.175% Moreover, an addition of 0.175% of Al2O3 nanoparticle in the baseline improved the average heat transfer coefficient from 140% to 155%, thermal conductivity of 21.6% and, 5.94% efficiency in counter flow direction and also showed higher friction factor i.e. 2.81% than baseline water. The results suggest that Al2O3-nanofluid at 0.175% could function very well as working fluid for industrial requirements compared to the conventional baseline water. [ABSTRACT FROM AUTHOR]

This study aims to numerically investigate the impact of air supply terminal devices (ASTDs) on the performance of novel variable refrigerant flow (VRF) integrated stratum ventilation (SV) system. The novel VRF-SV hybrid system was designed and analyzed in the authors' previous work, where different design configurations were tested and their performances were compared. However, the effect of ASTDs on the performance of novel system has not yet been thoroughly explored. Therefore, this study was designed to investigate the effect of four types of ASTDs, including bar grille, double deflection grille, drum louver and jet slot diffusers installed in the laboratory and meeting room environments. The temperature and velocity field distribution, thermal comfort and indoor air quality (IAQ) were examined as performance indicators. The Re-Normalization Group (RNG), Realizable and Standard k -ϵ turbulence models were also employed in this study to verify and validate the numerical predictions with the experimental measurements. The experimental results found relatively close to the predictions obtained through RNG k -ϵ model with maximum deviations at any location were found to be 0.28 m/s in terms of velocity and 1.6°C in terms of temperature magnitude. Further research demonstrated that among the studied ASTDs, the bar grille diffuser provided an adequate thermal environment for the occupants with an acceptable jet throw and IAQ. This benefit also suggests that if the bar grille is installed with the VRF-SV system, the system would require less fan power, and thus, it reduces the energy use by the fan. [ABSTRACT FROM AUTHOR]

This paper proposed a new approach for the efficient air conditioning of large tropical buildings. The current study has two objectives: the design and numerical investigations of the performance of vertically oriented high capacity linear slot diffusers (HCLSD) in an atrium building and the verification and validation of the different turbulence models through laboratory-scale experiments. The HCLSD was investigated with varying angles of inclination of the blades (ϕ = 0o to 25o) for the in-depth performance analyses. The performance was evaluated by monitoring and comparing the velocity and temperature profiles along the vertical lines drawn at different locations in the studied domain. A relatively longer jet throw was noticed through quantitative analysis at ϕ = 0o. Note that more than 33% increment in the face velocity was recorded at this angle. The corresponding terminal velocity of 0.225 m/s was observed at 8 m distance from the diffuser face. The detailed investigations at 0o deflector angle (case-1) were carried out for velocity, temperature field, and thermal comfort indices, i.e. PMV and PPD models. For the occupied zone, the thermal comfort indices were found within the acceptable ranges (i.e. PMV = + 0.1 to +0.9 and PPD = 4% to 20%). Abbreviations: ACMV: Air conditioning and mechanical ventilation; CFD: Computational fluid dynamics; CMH: Cubic meter per hour; DV: Displacement ventilation; HCLSD: High capacity linear slot diffuser; IAQ: Indoor air quality; MV: Mixing ventilation; PMV: Predicted mean vote; PPD: Predicted percentage dissatisfied; RANS: Reynolds-Averaged Navier – Stokes; RNG: Re-Normalization Group; SST: Shear-Stress Transport: SIMPLE: Semi-implicit method for pressure linked equations; VAV: Variable air volume; VSD: Variable speed drives [ABSTRACT FROM AUTHOR]

As the world becomes more urbanized, the market for petroleum products increases. The supply of crude oil-based products such as diesel, gasoline, and natural gas is limited. Furthermore, natural resources are finite and their reservoirs are located in certain parts of the globe. Countries with low to no fossil fuel resources are experiencing a scarcity of petroleum products, necessitating the exploration of alternative energy resources. In this research, tests regarding the exhaust particulate emission, sound pressure level, and performance have been carried out using samples from diesel and biodiesel (waste cooking oil) blended fuel. Two fuel samples have been used, B25 (biodiesel 25% and 75% diesel) and 100% diesel as a baseline in a CI engine at constant RPM of 1350 and variable loads of 0.0 to 1.6 at an interval of 0.2Kg-m. The results show that particulate emissions are reduced by about 7.29% when using biodiesel blended fuel, whereas brake-specific fuel consumption of biodiesel blended fuel has decreased as brake power increased, and brake thermal efficiency increased as brake power increased. The sound pressure level was measured from different locations of the engine (back, front, left) and for varying load. The results show that B25 produces less noise than D100 in each case. [ABSTRACT FROM AUTHOR]

Biodiesel is a renewable, safe, environmentally friendly, and significant source of energy which produces a lesser amount of greenhouse effect gasses. The biodiesel source is local chicken frying oil, synthesized by the trans-esterification process. In this research, the Particulate Matter (PM) exhaust gas emissions and sound emissions are examined. Emissions such as PM (PM1.0, PM2.5, PM7.0, and PM10), nitric oxides (i.e. NO and NO2), CO, CO2, and noise were investigated at variable loads with constant engine speed. Fuel samples, i.e. pure diesel (D100) and 20% Biodiesel (B20) and 30%Biodiesel (B30) blends were tested. Conventional diesel was found to emit more particulate and sound emissions, while B30 had lower emissions than B20 and conventional diesel. The lowest average values regarding exhaust gas emissions was 0.00690ppm for PM1.0, 7.44ppm for NO2, and 190.727ppm for CO, presented in B30. However, emissions from the engine decreased with increase in the blending ratio of biodiesel. Furthermore, the lowest average value of CO2 was found in B30 and was about 1.457%. [ABSTRACT FROM AUTHOR]

Seven quality control (7QC) tools are used for reducing defects during manufacturing. These tools are highly effective in productivity and quality improvement. In this case, the study of the 7QC tools was applied in an automotive factory in order to reduce paint shop defects. Within four months the production line was inspected, defects were categorized and the 7QC tools were successfully applied, reducing the overall defect rate by 70%. Although every tool was important, the cause and effect diagram was responsible for finding the root causes of the defects. [ABSTRACT FROM AUTHOR]

Composite materials have been used to resolve industrial problems. Considerable attention from the industrial side started in the 1960s with the introduction of polymer-based composite materials. Their advantages such as low weight (density), resistance to corrosion, high strength and low maintenance cost made composite materials an attractive substitute to conventional materials. A new composite material was developed with 10% natural fiber at 0o, 90o and 0/90o orientations resulting in ample improvements in the mechanical properties as compared to previous studies. The sample at 0/90o orientation gives the best results with tensile, tensile strength, tensile elongation and Young's Modulus values of 2458.19N, 4594.5MPA, 4.7% and 23.0 respectively. [ABSTRACT FROM AUTHOR]