Environmental pollution caused by burning fossil fuels, global warming, the greenhouse effect, and other factors has changed the approach of science to the use renewable energies. The main objective of this paper is to study the effects of diverse inputs (solar radiation) and collector geometries and also heat transfer of the solar chimney power plants (SCPP) model on the thermal and efficiency of

Technological developments are continuously growing to improve the efficiency of thermal systems on the demand of present era. To get rid of the scientists and engineers from traditional heat transfer intensification methods and to miniaturize thermal transport devices, novel and innovative techniques are obligatory. In this whole drive, the effective tube geometries and efficient working fluids perform

The objective of this article was to describe the osmotic dehydration of cubic pieces of melon immersed in solutions of water and sucrose, using a three-dimensional solution of the diffusion equation in Cartesian coordinates, considering the resistance to mass flows on the surface. Three experiments were conducted at room temperature, with no continuous stirring, at the concentrations of 25, 45 and

When simulating a daily performance of a solar thermal powered adsorption refrigeration system, daily weather data (i.e. daily maximum and minimum ambient temperatures and daily total solar radiation) are normally used to simulate a 24-h refrigeration cycle. However, the simulation obtained in this way is not that accurate, due to which could not reflect real hourly processes during the daytime. In

Numerous industrial applications of falling film flows alongside its heat and mass transfer complexities appreciate some deep and detailed studies. In order to recognize the influences of film flow rate on the modality of heat transfer coefficient, the falling flow of R-245fa at saturation pressure of 123.8 kPa around the horizontal tube has been simulated at different Reynolds numbers of 357, 500

Fouling in heat exchangers can complicate the characterisation and interpretation of thermal effects because of ageing phenomena that occur within the deposited fouling layer. The prevailing process temperatures between the liquid bulk and heat-transferring surfaces create a large thermal conductivity distribution according to the position of the layer within the deposit. During the growth phase, an

Tower type grain dryers are widely used in corn drying process and are manufactured as cylindrical structures with a height of about 30 m. Grain is filled into the annular section between the perforated walls and dried with exhaust gas from the combustion chamber. In terms of drying quality and energy efficiency, high capacity drying systems need a reliable control system. In the current study, a laboratory

In this study, nanostructures were fabricated on sintered copper powders through alloying-dealloying method for investigating and analyzing drop penetration and wetting characteristics. Based on the high-speed video imaging, the kinetics of droplets immersing process were studied for multi-scale composite compact (MCC), featured with the microns for copper particle sizes and nanometers for the surface

The experimental study of the frictional pressure drop characteristics of flow boiling heat transfer of CO2 in a horizontal minichannel with an inner diameter of Φ1.5 mm was carried out. Experimental conditions: heat flux (7.5 ~ 30 kW•m−2), mass flow rate (50 ~ 600 kg•m−2•s−1), saturation temperature (−40 ~ 0 °C), vapor quality (0 ~ 1). The comparison between the experimental results and theoretical

The solidification dynamics of cylindrical encapsulated PCM have been analyzed under convective boundary conditions that relate to thermal energy storage systems. A three dimensional, transient CFD model has been solved for examinations. Besides the widely used conduction model of solidification, in this study, the effect of natural convection within the liquid layer has been considered in the numerical

In this study, the cooling capacity and the pressure drop variation in an automobile radiator using nanofluid instead of water with antifreeze that are investigated experimentally. The nanofluid consisted of 50% Ethylene Glycol–Water mixture including Al2O3 nanoparticles with 0.5% volumetric concentration was used as coolant. In all experiments, the inlet temperature of the cooling fluid into the radiator

Thermal contact conductance (TCC) plays a vital role in improving the performance and the service life the electronic devices. As, the solid conduction paths through which the heat as to be dissipated includes multiple metal-metal and metal-dielectric contacts, which offers significant resistance to the rate of heat transfer. There exists a strong need for the estimation of TCC at the interface of

The effect of gravity on the dynamics of flow boiling channels is studied using linear and non-linear stability analysis tools. The developed tools are used to predict experimental results showing good agreement. The linear stability analysis shows that gravity enhances the density wave instability mechanism, enlarging the linear unstable region. Non-linear effects are then investigated by using Hopf

Our aim is to determine the more significant parameters acting on the water vapour condensation in a partly closed structure, submitted to external constraints (temperature and humidity). These constraints locally lead to condensation of the water vapour, initially contained in the air of the volume and/or on the walls. Previously we have presented the results obtained in two papers. In the first one

As far as design safety and operation of heat exchangers with a horizontal flow are concerned, it is necessary to study local heat transfer coefficient, boiling pressure drop, and critical heat flux for flow in a horizontal tube. In the present experimental work, local axial distribution of heat transfer coefficient, two-phase pressure drop, and critical heat flux for the flow boiling in a horizontal

The gas-phase mass transfer coefficient is one of the significant parameter for the determination of mass transfer in absorption columns. A novel correlation was obtained for the calculation of the gas phase mass transfer coefficient in the current research study based on the theoretical investigation and experimental data. Buckingham pi-theorem was utilized to develop an overall dimensionless correlation

In this paper, a new composite support made of steel and polymer is proposed for the internal supports of mobile cryogenic vessels. Multilayered design of the steel part in the presented support controls the heat transfer through this part by adding more thermal contact resistance (TCR) to the heat flow path. An analytical model is developed to calculate TCR between layers of the steel part at the

In this paper, the experimental study of heat transfer during condensation of freons R22 and R407С in a plain smooth tube with 17 mm inner diameter was carried out at saturated condensing temperature 40 °C, while mass velocity ranged between 6 and 57 kg/(m2s) and vapour quality changed from 0.23 to 0.95. The unique measurements of circumferential heat fluxes and heat transfer coefficients were performed

Nucleate boiling is an important part of the pool boiling phenomenon which occurs in various processes involving heat transfer, such as, steam production, chemical processes, etc. The inclination of the heated surface, where bubbles nucleates, significantly affects the bubble growth dynamics as well as the heat transfer rate from the microlayer underneath the bubble during the nucleate boiling. In

Film cooling performance of a novel double jet configuration is numerically analysed. The proposed scheme has a primary compound angle hole along with a secondary hole compounded in the laterally opposite direction. The primary hole is provided with a trench at the coolant hole exit. Numerical analysis is performed using RANS equations along with standard k-ω turbulence model. The numerical scheme

An experimental study combined with a mathematical modeling of vacuum drying of cocoa beans was carried out to enhance the drying kinetics without compromising the quality of dried products. Experiments were conducted to compare the effects of variation of temperature and pressure on the drying process. The temperature was varied between 40 and 60 °C, while the pressure between 735 and 245 mmHg. The

The effect of nanomaterials on the thermal behavior of Decanoic-Caprylic Acid (DA-CA) binary eutectic mixture was investigated experimentally. Different high thermal conductivity nanomaterials, including nano-sized iron oxide (Fe2O3), nano-sized copper (Cu), hydroxylated multi-walled carbon nanotubes (MWCNT-OH), and dispersant Span-60, were added into DA-CA, respectively. The nanomaterial-enhanced

Heat transfer enhancement in thermal systems has great importance in achieving better performances at decreased spaces. In the present work, by combining two passive enhancement methods of using miniaturized channels and utilizing nanofluid, the heat transfer from a heated surface is investigated. In this regard, the thermal performance of an Aluminum minichannel heat sink with rectangular cross-sections

The present study deals with an experimental and numerical study to quantify the skin necrosis during cryotherapy. Agarose gel (0.6% (w/v)) is used to mimic the thermal properties of the dermis. The spray cooling is performed with 0.8 mm, 0.6 mm and 0.4 mm nozzle diameters for a single freeze-thaw cycle of 120 s freezing and 130 s thawing. The distance from the nozzle to the gel surface (z) is maintained

This study investigates the pressure drop in horizontal pipes packed with large particles that result in small pipe-to-particle diameter ratio both experimentally and numerically. Two horizontal pipes of 0.1905 and 0.0254 m ID filled with cylindrical or spherical particles are used to collect the experimental data for single and two-phase flows. The porosity has same value for both pipes when they

This study investigates the thermal performance of square pin-fin heat sinks for different operating conditions including different heat flux and different Reynolds numbers. Two heat sinks with different sizes of copper square pin-fins cross section (2-mm fins and 500-μm fins) in-line arranged are experimentally investigated to determine their thermal performance quantified in terms of thermal resistance

With a single-phase approach, a 3D mathematical model was developed through Computational Fluid Dynamics (CFD) techniques, coupling the momentum and heat transfer balances for the study of the thermal behaviour of nanofluids. The local heat transfer coefficient and thermal boundary layer thickness of CuO/water, Fe2O3/water and Al2O3/water nanofluids, have been predicted and compared with those experimentally

The affiliation of the sixth author

The experimental analysis is arranged to evaluate thermal hydraulic performance on flow of fluid in the tube with helical screw inserts at numbers of strips and different values of twist ratio at transition flow regime. Single strip helical screw insert is also compared with double strip helical screw inserts at values of twist ratio. Further, the CFD analysis is carried out to visualize thermohydraulic

Operation parameters restrict the performance of hydrocyclone in offshore platforms. Based on the computational fluid dynamics (CFD) software Fluent and the similarity parameter criterion experiment, the numerical simulation of the separation flow field and separation efficiency of hydrocyclone at different feed solid concentration was carried out, taking short circuit flow into account, a new correcting

In this paper, the effect of two-phase interface morphology evolution on the flow and heat transfer characteristics in confined channels are reviewed in detail, which is one of the typical channel structures for the nuclear reactor core. The investigated contents mainly come from the open literature. In addition, this paper focuses on the important phenomena and methods proposed in recent decades,

An enormous amount of heat energy is available in the cyclone and downcomer of a circulating fluidized bed (CFB). The downcomer section can thus be a major source of heat recovery. There is scope for investigation on prospects of recovering heat along the downcomer. In the present work, an attempt is made to utilize the heat from the downcomer of a laboratory-scale Pressurized circulating fluidized

An experimental study on the dynamic thermal environment and front and rear occupants’ local thermal sensation of the vehicle cabin in automatic air conditioning mode under different driving states in summer is conducted. Experimental results show: air temperature, occupant skin temperature and local thermal sensation are all affected by crew position, body part and driving status. Driving increases

Flooding limit is the most severe limitation in the operation of a two-phase closed thermosyphon (TPCT). However, the effect of condenser length to the critical heat flux (CHF) and the influences of structural and operational parameters to the critical liquid film thickness (CFT) were not universally concerned. In the present study, a comprehensive model for TPCT is developed to predict the CHF and

A 3D numerical study of water spray flash evaporation occurring in a positive-pressure saturated vapor environment is conducted. The spray is non-uniform with a Rosin-Rammler droplet size distribution. The characteristics of the flashing spray and vapor flow field are obtained by calculating within the Eulerian-Lagrangian framework. The spray undergoes violent evaporation and significant temperature

Experiments were performed to demonstrate the impact of surface wettability on the nucleate boiling heat transfer of Silicon Dioxide (SiO2) Thin Film (TF) nanocoated surfaces using the saturated refrigerant R-141b at atmospheric pressure. Six numbers of circular flat type test sections of copper material having thickness of 0 nm (plain surface), 125 nm, 250 nm 375 nm, 500 nm and 625 nm surface coating

A small plate heat exchanger filled with copper foam which can be applied for small scale electronic cooling is presented. The heat transfer coefficient and pressure drop of water flow inside a plate heat exchanger filled with copper foam (PHECF) are experimentally studied. The effect of copper foam pore density and water velocity on the optimum thermal performance is also presented. The experiment

In this study, two types of adsorbents, Molecular sieve 3 Å and Silica gel 8–20 mesh were used for CO2 separation from CO2/N2 mixture in a fixed bed column. The impact of the temperature, superficial velocity and CO2 partial pressure on the breakthrough behavior, adsorption capacity and mass transfer zone has been thoroughly investigated. The breakpoint time declined with increased temperature, and

Fog on the automotive windshield interferes with the sight of the driver and causes serious safety problems; thus, removing it rapidly has been a longstanding goal in the automobile industry. In this study, we propose a novel method for improving the defogging performance of the defroster without its structural alteration by using vortex generators (VGs). To optimize the performance of the VGs, we

The two-tank thermal energy storage system with a mixture of sodium nitrate and potassium nitrate is one of the most common ways in concentrated solar power plants. However, the unreasonable thermal performance of tank foundations such as excessive heat loss and overheating of concrete slab could result in local molten salt solidification and foundation settlement. This work proposes a novel foundation

In order to enhance thermal efficiency, most process industries are fitted with heat exchangers. Without using external power, we can increase the heat transfer rate by providing different strips in tubes. This paper deals with the passive method of elliptic leaf insertion in a double pipe heat exchanger with opposite orientation and same direction and the heat transfer rate and pressure drop are found

To evaluate turbulent heat transfer on rotating turbine blades, knowledge of the Reynolds stress and heat conduction moments on the blades is required. This involves solving the mean flow equations of momentum and thermal energy on the rotating blades. In this paper, the turbine blades are represented by rotating curved surfaces, and turbulent heat transfer calculations are carried out by invoking

Polymer based composite materials have a great potential for applications in tribology as dry lubricants since the components comprising the composition may be chosen to fit to various tribological requirements. It is however well known that heat transfer and thermal effects are important for such systems. Systematic experimental studies of temperature effects are time consuming and expensive. In this

In present communication, a solar dryer having semi-transparent photovoltaic thermal (SPVT) roof has been used to dry bitter gourd. Experimentation has been done and results were validated with linear regression method through mathematical modelling as well as for non-linear Artificial Neural Network (ANN) modelling has been used. The experimental data namely, ambient air temperature, moisture evaporated

The purpose of this study is to investigate the effect of spiral springs with the square cross-section area on heat transfer and pressure drop in heat exchangers. The springs were fitted inside a circular cross-section copper tube. The diameter and length of the copper tube were 25.4 mm and 1820 mm, respectively. The experiments were performed with 9 spiral springs of 12 and 15 mm diameter in four

In hot and humid climates, the evaporative cooling system not works effectively. To reduce the relative humidity of inlet air, the reciprocating desiccant mesh (RDM) is introduced before the cooling tower. The cooling tower is fabricated as per the Merkel’s theory and RDM is placed before the cooling tower. Experiments have been conducted to compare the performance of normal and RDM cooling towers

Over the past decade, different variants of desiccant cooling system integrated with direct/indirect evaporative cooler(s) have been simulated and/or analyzed in specific climatic conditions under rather limited operating parameters and for limited durations of time. Complete seasonal and multi-climate performance analyses of solar desiccant cooling system integrated with efficient, indirect Maisotsenko

Over the past few decades, experimental studies have been conducted on the condensation heat transfer of vapor mixtures. However, the local heat transfer characteristics of vapor mixture affected by surface tension have not been fully investigated. The present work, for the first time, suggested the CFD simulation method for the Marangoni condensation of ethanol-vapor mixture and analyzed the calculated

Droplet formation in a flow-focusing device was modeled using the open source CFD package, OpenFOAM, with the VOF model for two-phase flow. Predictions using the interFoam solver and a power-law non-Newtonian model were first validated against experimental data in the literature. Then, the formation of Newtonian fluid droplets in power-law fluids was modeled during tubing, squeezing, dripping and jetting

Unsteady boiling bubble behavior of water in a square pipe under a low pressure and subjected to natural convection was experimentally studied. The measurements included temperature and pressure, and the bubble behavior was visualized using a high-speed camera. The boiling phenomena in the pipe showed the three stages characterized by cavitation, intermediate, and fully developed boiling bubble in

Numerical simulation of the influence of operating conditions of the furnace on its performance characteristics like heat flux distribution, Furnace Exit Gas Temperature (FEGT) and NOx emission levels was performed for a tangentially fired pulverised coal boiler. The results revealed that the FEGT and NOx emission are slightly higher when the top seven coal nozzles are in operation compared to the

For exploring the complex heat and mass transfer in the micro-particle fixed bed, the device to measure thermal conductivity was designed and built. The experiments showed that the error was less than 2.97% after calibrated, and reproducibility was good. Effects of particles diameters, porosity, flow rate and ion exchange on the thermal conductivity of micro-particle porous materials were investigated

In this experimental study, the influence of combined passive technique on heat transfer, friction factor, and thermal performance factor are investigated in a double pipe heat exchanger fitted with different turbulators and GO-Water nanofluid. Experiments were conducted for a fixed flow rate of (Re = 2500) in the inner tube (hot fluid); for varying flow rates (500 ≤ Re ≤ 5000) and volume concentrations

Fouling still remains one of the most difficult problems for the use of heat exchangers. A methodological process of advanced analysis of experimental data on heat exchangers fouling allowing building predictive models is necessary to determine the fouling degree. Here, three different methods were used to predict the fouling resistance from some easily measurable variables of the system which are:

Improving building energy efficiency is one of the most important challenges towards the mitigation of climate change concerns. Buildings use significant amount of energy for cooling loads. Development of new night-time and day-time radiative cooling modalities by roofs is essential for reducing the energy consumption during the summer months. If a surface is desired to be kept cool while exposed to

The application of fully pulsatile flow in liquid-liquid two-phase extraction contributes to augment the interfacial mass transfer. Further, the inclusion of air at the top of the central test section combined with pulsatile flow augments the extraction or the mass transfer process. Toluene-water is chosen as an organic-aqueous two-phase liquid-liquid system with acetic acid as the transfer species

A unique boiling heat transfer study of wetting fluids in a vertical three-dimensional rectangle microchannel was carried out in this paper, to develop a novel passive three-dimensional chip stack cooling technology. The base liquids were deionized water and R113, and Sodium dodecagon sulfate (SDS) was used as a surfactant, which is added into the base fluids for developing wetting fluids. The length

The results obtained from a drying experiment using infrared heating are compared to those obtained from an analytical model based on correlations for the mass transfer coefficients, which are commonly used to obtain evaporation rates for drying applications. It was shown that the mass transfer coefficients calculated by natural convection correlations are approximately ten times lower than those measured

Fouling of heat exchangers in energy and power plant industry, oil and gas industry, pharmaceutical and food process industry, industrial waste heat recovery is a major problem which needs to be solved urgently. In the United Arab Emirates, a majority of oil & gas processing plants are located in the desert where water accessibility is limited, thus fin-fan type of heat exchangers are used for cooling