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This study presented theoretical and simulation predictions to find the optimum glass cover inclination angle that can allow the water droplet underneath the surface to slide along it without fall-off. As a case study, the solar still main component that plays a big role on it is performance is the transparent glass cover that permits solar rays to pass through it and is used as a condensation surface for water vapor. The inclination angle of the cover is a very important parameter that provides confined space to increase the condensation process by fast cooling of the surface and result in more freshwater productivity. The theoretical prediction is obtained by modeling a set of mathematical equations that contain the main parameters necessary to slide the droplet along the surface without detaching it and solving them by using the MATLAB computer program. The simulation technique for the volume of fluid method uses the volume fraction equation with the level set applied in ANSYS Fluent software. The 3D model was created, and a water droplet was applied with adhesion force on the glass. It was found that the size of the droplet represented by its critical radius is a function of inclination angle. Also, it is found that for the angles larger than 15o , water droplets slide over the surface without separation. The optimum cover inclination provides both smooth slidings of droplets along with it and a suitable confined area that increases the rate of evaporation and condensation.

Pickup truck serves purpose as car as well as small truck. Pickup truck is popularly used in USA and Saudi Arabia. Pickup truck consists of enclosed cab and an open cargo space. Here CFD analysis of full scale pickup truck is performed using free CFD software OpenFOAM for speed range from 40km/hr to 140km/hr. For turbulence modelling k-ω model is used. This work investigates effect of covering cargo area on aerodynamics drag. Covering cargo area decreases drag coefficient by 5.2% by horizontally covering cargo area whereas decreases by 13% by inclined surface covering cargo area. Thus, covering cargo area reduces drag coefficient as recirculation zone is reduced. Inclined cover case shows drastic rise in lift force, requiring attention for safety as traction will be affected.

In this article, CFD analysis carried out to study the flow Characteristics due to the effect of offsetting in platoon of Sport Utility Vehicles (SUVs) using OpenFOAM software. Platoon of three bodies of SUV in tandem are considered. Effect of spacing of SUV platoon on drag coefficient assessed. CFD analysis of full scale SUV performed at speed of 80 km/hr for vehicle spacing from 0.25 to 2 times length of SUV It is observed that average drag coefficient of platoon is lower than that of standalone single SUV for range of spacing considered by 24%. Thus effect of platooning results in fuel saving. Also effect of offset of middle car in platoon by 10%, 20% and 30% assessed on average drag coefficient of platoon. Offset of middle car in platoon results in increased platoon average drag coefficient to extend of 6.61% as compared to inline platoon. Thus in platooning it is better to maintain SUV straight-line to get full benefit of platooning.

Due to the current circumstances of the Corona pandemic, the world has resorted to stopping direct learning and has shifted toward e- learning. However, there appeared obstacles encountered in the e-learning process, namely the practical skills and laboratory experiments that students need to supplement the teaching process. Virtual Reality (VR) techniques can provide models for experimentation with low cost in addition to the time factor savings. The main goal is for adopting an idea to use virtual reality software programs in designing scientific experiments as an alternative method for direct teaching of laboratories. In this study, the perceptions, attitudes and future aspiration of the faculty members of engineering colleges take by questionnaire about the ability to use virtual reality technology in the implementation and design of practical experiments and achieving the targeted educational outcomes.The results showed a low percentage use of VR in teaching engineering experiments because this is a new technology and there is a shortage of infrastructures such as equipment, hardware and software in addition to unavailability of workshops and training courses for faculty members and laboratory supervisors. The results also revealed positive perceptions about the importance of VR in distance learning and negative attitudes in adopting VR as an alternative method of teaching engineering experiments.

— This article advises a simple and innovative scheme for generating electricity from human activities. A simple and robust approach is proposed for converting human walking into valuable electricity source. The proposed scheme could be sufficient for powering small portable devices and providing independent power supply. Matlab and Simulink dynamic platform are used for stimulating the systems under concern. The prototype results validate the simulation results. The proposed scheme proofed to be valuable, economical and reliable power supply.

In this paper, a ferrofluid-based cooling technique is proposed for solar photovoltaic (PV) systems, where ferrofluid flow can be easily altered by the application of an external magnetic field leading to enhanced heat transfer from the hot surface of PV systems. The effect of both constant and alternating magnetic field on ferrofluid flow through a minichannel is explored numerically in the present work. A detailed parametric study is performed to investigate the effect of actuation frequencies of alternating magnetic field (0.5–20 Hz) and Reynolds numbers (Re = 24, 60, and 100) on heat transfer characteristics of ferrofluid. An overall enhancement of 17.41% is observed for heat transfer of ferrofluid in the presence of magnetic field compared to the base case of no magnetic field. For the case of alternating magnetic field, a critical actuation frequency is observed for each Reynolds number above which heat transfer is observed to decrease. The enhancement or decrease in heat transfer of ferrofluid is found to depend on several factors such as actuation frequency of alternating magnetic field, Reynolds numbers of ferrofluid flow, and formation/dispersion of stagnant layers of ferrofluid at the magnet location. Preliminary visualization of ferrofluid flow is also carried out to provide a qualitative insight to the nature of transportation of ferrofluid in the presence of an alternating magnetic field.

Solar energy is considered as an available source of huge amount of thermal energy with low cost and it is environmentally friendly. Seawater desalination is the main source of freshwater in many countries using different technologies. Seawater desalination using solar thermal energy with passive techniques is vital for arid areas that have shortage in electricity grids or any other sources of energy. In this study, an experimental investigation for a solar still with pyramidal cover in the environmental conditions of arid regions in Saudi Arabia has been conducted. The pyramid surfaces have been designed and directed so that one of the faces receives sunlight directly for a period, which helps in the process of evaporation faster, and the other interface is away from the rays so that the temperature is low to help in the process of condensation of steam. In addition, a seawater feeding system is designed to maintain a constant level of water height within the basin. The accumulated freshwater productivity along sun shining period of the day has reached 3230 gm and the instantaneous productivity takes place at the maximum irradiance period and it has reached 472 gm. The energy and the exergy analyses for the system have indicated that the energy and the exergy efficiencies of the system have reached a maximum of 60% and 5%, respectively. The over day energy and exergy efficiencies of the system have been 31.6% and 2.35%, respectively. The produced freshwater cost from the system has been found out to be 0.1 $/L/m2.

Experimental and analytical investigation was carried out to show the effect of surface tension on the heat transfer coefficient of gas flow inside micropipe heat exchangers during the condensation process. An empirical correlation was formulated for the coefficient of the convective heat transfer. A comprehensive comparison between the experimental results with published correlations in the literature and that obtained by the developed correlation was conducted. The results showed that the predicted heat transfer coefficient of the proposed correlation was closer to the experimental results than any other correlation, a finding related to the consideration of the surface tension.

An experimental study on single-phase laminar forced convection in a single porous tube heat exchanger is presented. Parametric studies are conducted for different inlet pressures, different mass flow rates, and different porosities to evaluate the effects of particle diameter and Reynolds number on the heat transfer and friction factor. The Nusselt number and friction factor are developed for efficient design of a porous heat exchanger based on the present configuration. Heat is transferred to the walls of the heat exchanger by natural convection mode. Gravel sand with different porosities is used as a porous medium during the tests. The flow of carbon dioxide as a working fluid in the porous medium is modeled using the Brinkman–Forchheimer-extended Darcy model. A dimensionless performance parameter is developed in order to be used in evaluating the porous tube heat exchanger based on both the heat transfer enhancement and the associated pressure drop. The study covers a wide range of inlet pressures (Pi), mass flow rates ( ), porosity of gravel sand (e), and particle diameters (dm) which ranged 34.5 ≤ Pi ≤ 43 bars, 8 ∗ 10−5 ≤ ≤ 16 ∗ 10−5 kg/s, 34.9% ≤ e ≤ 44.5%, 1.25 ≤ dm ≤ 5.15 mm, respectively. This study revealed that a smaller particle diameter can be used to achieve higher heat transfer enhancement, but a larger particle diameter leads to a more efficient performance based on heat transfer enhancement. The average heat transfer coefficient of carbon dioxide decreases when the porosity increases. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21059

Three different types of heat exchangers were tested experimentally to investigate two-phase heat transfer coefficient and pressure drop during the condensation process of CO2 gas. Experimental results revealed that the convection heat transfer coefficient was enhanced by a factor of four due to the existence of porous media and by a factor of seven due to the use of micro-pipes when compared to the normal macro-tubes. The pressure drop was measured and noticed only in porous tubes and micro-pipes, reaching about 17.5 kPa/m and 8.4 kPa/m, respectively. Comparisons between experimental and correlated results were conducted.

The increasing fossil fuel costs have led the world to use the clean and naturally available energy from the sun to produce electric power. Parabolic trough technology is nowadays the most extended solar system for electricity production or steam generation for industrial processes. It is the most proven, lowest cost and large-scale solar power technology available today. It is basically composed of a concentrator collector field which converts solar irradiation into thermal energy that will be used as input for a Rankine power cycle. In such plants, a storage system can be implemented in order to increase plant production. This work aimed to conclude with a simulation model of a solar thermal power plant using a parabol solar concentrator. The Euro Trough (ET) Concentrator was used as case study. MATLAB software was used for the analysis and performance evaluation. Different working fluids were used in the simulation which were: Pressurized water, Boiling water and Oil (Therminol-VP1). It was found that using water (pressurized or boiling) in the receiver tube is better than the Therminol-VP1 oil. And the pressurized water has the highest value of efficiency compared to the boiling water and Therminol-VP1 oil. The oil using system presented the highest energy losses system, and the lowest efficiencies. The ET performance was tested at different places in Jordan, and the distribution of direct solar irradiance at different days around the year was calculate and exhibited for Ma’an city as a case study. A comparison between simulated results and that found in literature were carried out with observed good conformity.

In this work an easy to use, simple and direct equations were formulated and tested. Heat transfer coefficients of phase change fluid flow were examined in this work. The considered fluid flow encountered convection heat flux inside rigid tubes filled with porous media. During the flow, phase change was assumed. Experimental work was conducted using Carbon dioxide as fluid. An analytical method using exponential non dimensional analysis was used. The Buckingham π theorem and method of indices was used to obtain simplified formula for the convection heat transfer coefficient and for the Nusselt number. Two different correlations can be extracted from this formula; one for the evaporation process and the other for the condensation process.

In this paper, the experimental results of the convection heat transfer coefficient and pressure drop values during condensation and evaporation of CO2 were obtained at different operating conditions for flow inside micropipes. Reynolds number (ReD) ranged between 2000 and 15000. The dimensional analysis technique was utilized to develop correlations for Nusselt numbers and pressure drops. A comparison between experimental and correlated results was carried out. The results showed that for the condensation process, the bias errors were 5.25% and 0.4% for pressure drops and Nusselt number respectively. Consequently, Average Standard Deviation (ASD) values reached 17.94% and 4.62% for both respectively. On the other hand, for the evaporation process, the Nusselt number error was 3.8% with an ASD of 4.14%. The correlations presented in the present work can be used in calculating pressure drops and heat transfer coefficients for phase change flows in mini and micro tubes. It helps to enhance design calculations of heat exchangers, condensers and evaporators

The increasing fossil fuel costs have led the world to use the free and naturally available energy from the sun to produce electric power. Parabolic trough technology is nowadays the most extended solar system for electricity production or steam generation for industrial processes. It is the most proven, lowest cost and large-scale solar power technology available today. It is basically composed of a concentrator collector field which converts solar irradiation into thermal energy which will be used as input for a Rankine power cycle. In such plants, a storage system can be implemented in order to increase plant production. This work aimed to conclude with a simulation model of a solar thermal power plant using a parabolic solar concentrator. The Euro Trough (ET) Concentrator was used as case study. MATLAB software was used for the analysis and performance evaluation. Different working fluids were used in the simulation which were: Pressurized water, Boiling water and Oil (Therminol-VP1). It was found that using water (pressurized or boiling) in the receiver tube is better than the Therminol-VP1 oil. And the pressurized water has the highest value of efficiency compared to the boiling water and Therminol-VP1 oil. The oil using system presented the highest energy losses system, and the lowest efficiencies. The ET performance was tested at different places in Jordan, and the distribution of direct solar irradiance at different days around the year was calculate and exhibited for Ma’an city as a case study. A comparison between simulated results and that found in literature were carried out with good conformity observed.