The temperature and turbidity characters of an enhanced solar pond are studied by the indoor and outdoor experiments. Indoor experiments are carried out to analyze the ability of heat storage and turbidity restriction of varies porous materials. Outdoor comparison experiments between two mini solar ponds with surface area of 2.4m×2.4m and bottom area of 1m×1m are conducted to study the effects of different

The recent environmental degradation has generated a need for efficient energy devices. The performance of an array of jets impingement system can be augmented by using working fluids of better thermal properties compared to the conventional base fluids. In the current study, Reynolds-averaged Navier-Stokes (RANS)-based numerical investigation is carried out to compare the performance of the multiple

In the process of design of the turbine jet aircraft engine, one of the most important roles is thermal analysis. Without knowledge about the value and distribution of the temperature fields of aircraft engine parts (e.g. turbine), it is impossible to estimate the strength and life cycle of the turbine jet engine as well as its durability and reliability. Information about them contributes to the improvement

The study deals with the energy and exergy analyses of the drying process of corn dryer. Corn with average initial moisture content of 24% dry base (d.b) were dried until they reached a final moisture content of 15% (d.b) at temperatures of 103 °C in 60 min. The drying experiments were conducted at two different drying air velocity 2.8 m s-1 and 3.5 m s-1. The effective diffusion coefficient (Deff)

The enhanced heat transfer mechanism and parameter optimization of an interrupted microchannel heat sink with rectangular ribs (IMCHS-R) was numerically studied for Reynolds number ranging from 100 to 900, using ANSYS Fluent. Interrupted microchannel heat sinks with different kinds of rectangular ribs having different width, length and locations were compared with a straight microchannel and microchannel

In the present work, the effects of two synthetic jet orientations on the Nusselt number during combined convection heat transfer are investigated. The experimental study was conducted using two synthetic jet orientations−horizontal and vertical, and eight different Reynolds numbers, ranging from 0 to 1440. The temperatures were measured by using five thermocouples positioned at different locations

In this paper, a three dimensional numerical model of fully developed periodic flow in a CWPSR (Cross Wavy Primary Surface Recuperator) of a micro-gas turbine system was established. Effect of air hole leakage on flow and heat transfer of high temperature gas core and compressed air core was analyzed. Analysis results show that with leakage of air hole considered, flow velocity of compressed air from

A numerical investigation is carried out on the pressure drop and heat transfer performance of a compact U-shaped-tube bundle heat exchanger in a rectangular channel. The compact exchanger is modeled as a porous matrix. By using dual meshes method, the external flow and the internal flow are allowed to be solved simultaneously and the two flows be coupled only through heat transfer at the heat exchanger

Nanofluid suspensions have become the working fluid of the nowadays’ heat transfer implementations due to their distinguished behaviours on convective heat transfer. Boiling heat transfer which provides high heat fluxes is a kind of convective heat transfer, and thereby, thermal performance of a such mechanism largely depends on the working fluid type utilized. In this study, heat transfer characteristics

Brakes are one of the most important components of any machine with moving parts, but most of all - vehicles. In most cases, these are friction brakes. Their operating principle is based on the transformation of kinetic energy of motion into thermal energy. It is important that the brakes have the same, constant parameters of operation and the stability of the coefficient of friction throughout their

In this research, the effect of nanofluids including Al2O3 and water on the heat transfer enhancement in heat Exchangers with rotating straight inner tube were examined. Nano-fluids including Al2O3 and water were obtained at 0.25 and 0.5%volume concentrations by means of pure water as a base fluid. The aim of the study is to experimentally investigate and compare the influence of straight inner tube

The current moving heat source method lacks a reasonable heat source model and cannot realize a heat source rotates around on the tread for simulating the wheel/rail contact temperature under partial sliding condition. Based on the principle of energy equivalence, an elliptic cylinder model of heat source matching the shape and size of the wheel/rail contact patch was created. By writing a Fortran

An experimental analysis is made to measure the heat transfer, friction factor, thermal performance and effectiveness of Copper/water nanofluids flow in a double pipe U-bend heat exchanger. The Cu nanoparticles are synthesized using chemical reduction method and stable nanofluids are prepared by mixing them in distilled water. The experiments are conducted in the Reynolds number range from 3000 to

To evaluate the effect of structural improvement on the cooling capacity in three zones for natural draft wet cooling towers (NDWCTs) accurately, based on field test, this paper conducted the comparative studies for the cooling capacity in every zone before and after structural improvement, and analyzed the changing rules of three parameters αs, αf and αr with crosswind. The results demonstrated that

The characteristics of today's economy make it closely related to, and even dependent on efficient transport. For this reason a large number of transport vehicle combinations could be found on the roads, most often consisting of a tractor unit and a semi-trailer. These are large and heavy vehicles, which pose a potential threat to other road users. Therefore, it is important that their braking systems

On August 13-16, 2019, the 5th International Workshop on Heat-Mass Transfer Advances for Energy Conservation and Pollution Control (IWHT2019) was successfully held in Novosibirsk, Russia. The hosts were Kutateladze Institute of Thermophysics and Novosibirsk State University. The sponsors included the Kutateladze Institute of Thermophysics, Technopark of Novosibirsk Akademgorodok (Akadempark), Novosibirsk

The icing on the aircraft induces a severe problem for the safety, and development of the simulation method has been required. In the present study, the effects of several icing conditions consisting of inflow velocity, liquid water content and angle of attack, on ice accretion on an airfoil are numerically investigated using a particle-based method. The computational target is NACA0012 airfoil with

The conventional fluids used for heat transfer can not provide the desired thermal performance due to their poor heat transfer characteristics. Disadvantages of the base fluids can be overcome by forming a suspension of nanoparticles with the base fluid. In this work, the effects of using dolomite/deionized water nanofluid on thermal performance of thermosyphon heat pipe were experimentally investigated

The purpose of this study is to explore the heat dissipation efficiency of piezoelectric fan with different type heat sinks by changing the piezoelectric fan height which is relative to three different heat sinks. This study use flow visualization technique with driven by 110V, 60Hz and fix the amplitude range of piezoelectric fan and distance (0.5 mm,1mm,2mm,3mm,4mm,5mm and 7mm) between blade tip

In this paper, the cavitating flow performance of a cavitation Venturi tube was studied to obtain the steady flow curve and predict the cavitation region based on the realizable k-ε turbulence model and Zwart（Zwart-Gerber-Belamri）cavitation model under the designated conditions. Venturi tubes with different throat diameters of 12mm, 10mm and 8mm were selected respectively, and the distance between

In this study, Eulerian multiphase model coupled with the Rensselaer Polytechnic Institute (RPI) wall boiling model and SST k-ω turbulence model is utilized to analyse the subcooled flow boiling heat transfer in a circular vertical boiler tube under constant wall heat flux boundary condition. The numerical model is validated with the experimental results reported in the published literatures. Further

In this work, we get the exact solution of a nonlinear model of the thermal shock problem of generalized thermoelastic half-space of temperature dependent materials. We considered two different cases of temperature dependent materials. Finite element analysis technique is used to get the numerical solutions. The results for the temperature increment, the displacement, and the stress distributions are

To further enhance pool boiling heat transfer , an new oscillation device was proposed. An oscillating plate was located over the heater surface with a vertical oscillation amplitude of 20mm and frequency of 6 HZ. Three N-type phosphorus-doped silicon chips were used as heater surfaces. One was smooth surface, and the other two were micro-pin-finned chips having fin thickness of 30 μm and fin height

This article presents an experimental study on the effect of temperature and solid volume fraction of nanoparticles on the dynamic viscosity for the CuO/EG-water nanofluid. nanoparticles with diameter of 40 nm are used in the present study to prepare nanofluid by two-step method. A “Brookfield viscometer” has been used to measure the dynamic viscosity of nanofluid with solid volume fraction up to 2%

This study is carried out by using numerical simulations to investigate the effect of target surface curvature and the nozzle-to-target surface distance on the flow structure and heat transfer characteristics in a pin-finned double-wall cooling structure. The flow is directly impinging on the target surface and is disturbed by the pin fins, and then released from the film holes after passing the double-wall

Any substance has a critical point which is obtained at certain conditions of pressure and temperature. When a fl uid is subjected to a pressure and a temperature higher than its critical point, the fl uid is said to be supercritical. In the supercritical region, the thermophysical properties exhibit unique behavior and have intermediate values between those of a liquid and a gas. The supercritical

The aim of the present work is to reveal the heat transfer characteristics of S-CO2 tube and flue gas in the S-CO2 coal-fired boiler. According to structural features of wall heaters of the S-CO2 boiler, the wall heaters are modeled as the full-tube/half-tube. The heat transfer characteristics of full-tube and half-tube are compared by the numerical methods. For different coal-fired flue gas temperatures

To explore the vapor-liquid flow characteristics and heat transfer mechanism of propane, the flow boiling heat transfer process in a horizontal smooth copper tube with an inner diameter of 6 mm and an effective length of 900 mm is numerically simulated by the volume of flow (VOF) multiphase model using the FLUENT. The profiles of flow pattern, temperature, and velocity are obtained, while the effects

Simulation results on three-dimensional freezing phenomena around a cryoprobe are presented in the manuscript. Both fixed-grid explicit and implicit schemes based on the effective heat capacity method have been employed to solve the system of governing equations. The study revealed that the grid size of 1 mm and less is adequate to model the freezing process in the cryosurgical applications. Based

Current climate changes are leading to an increase in the intensity and frequency of extreme events with a strong impact on agriculture. Late frosts are one of the main calamities for fruit trees and are a major cause of loss and reduction of productivity worldwide. With regard to the wine sector, the late frosts lead to the destruction of thousands of hectares of vineyards, with economic losses occurring

A novel shell-and-tube heat exchanger with twisted fluid flow on the shell side is presented. To evaluate the performance, the characteristics of twisted flow and fully developed regions of fluid flow and heat transfer are analyzed numerically and experimentally. The overall structure numerical model of the heat exchanger has been established. A laser Doppler velocimeter (LDV) experiment was carried

In this study, the specific heat values of yttrium oxide-water nanofluid prepared in five different volumetric concentrations using Y2O3 nanoparticles were measured experimentally using the DTA method. Using the experimental results obtained, multilayer perceptron, feed-forward back-propagation artificial neural network with 15 neurons in its hidden layer was developed. Forty-two of the total 60 experimental

During the braking process many undesirable effects can appear that can disturb the safety of all participants in the traffic. It can be considered that using the new alternative friction materials is the key to improve the performance of brake system and reduce the negative effect on the environment. In this research paper, the temperatures and the stresses that appeared during the braking process

A theoretical model for flow boiling liquid film evaporation of zeotropic mixtures was proposed based on the film theory. Taking into account the mass transfer process in both the liquid and vapor phases, the mass transfer coefficient in the liquid concentration boundary layer was modified in this model. The calculated accuracy of this model was well validated by Takamatsu's experiments. The flow boiling

Sodium carboxymethyl cellulose (SCMC) effectively inhibits the growth of calcium carbonate (CaCO3) scale. In order to investigate the effect of temperature on the scale inhibition of SCMC, dynamics simulations were carried out for the amorphous calcium carbonate and crystal calcite system based on molecular dynamics simulation. The effect of temperature on the scale inhibition mechanism of SCMC has

People spend most of their lives indoors today. Therefore, the importance of indoor air quality increases with each passing day, particularly, when the current quality of life expectations is taken into consideration. One of the factors affecting indoor air quality is the amount of CO2 in the air. In this study, by using an air-handling unit (AHU) with plate heat recovery, the correlation of CO2 concentration

The heat transfer and resistance performances of heat exchangers with symmetric, asymmetric, and helical corrugated tubes are investigated experimentally. Numerical simulations are conducted to examine the mechanism of thermodynamics and fluid flow. The total heat transfer efficiency of heat exchangers using these tubes is analyzed, and optimal velocity matching values are presented. The results demonstrate

Aiming at the accuracy and adaptability of the structure model and numerical model of the selective catalytic reduction (SCR) denitration device and the uniformity reaction in it, the characteristic structures affecting the accurate calculation of the flue gas flow field, the method and rationality of the parameter setting used in the porous medium model, the theory and rationality of parameter setting

This work presents the experimental and numerical simulation results on convective heat transfer of a circular tube and an oval-shaped tube with the ratios of 1:1.425, 1:2.075, and 1:2.625 over a wide Reynolds number range. The aerodynamic and heat transfer characteristics of oval-shaped and circular tubes such as total drag, pressure losses, distributions of pressure, surface friction, and local heat

In this study, the performance pattern of air-driven two parallel-connected Ranque-Hilsch vortex tubes (RHVT) by using artificial neural network (ANN) is considered. Different parameters such as vortex tube inlet parameters, type of working fluid, nozzle material, and nozzle number affect the temperature separation in vortex tubes. In this context, overall temperature difference (ΔT), which is also

With the rapid spread of renewable energy, pulverized-fired (PF) power plants are forced to participate in load cycling to ensure peak modulation and balance electricity demand and supply. The load fluctuation for PF power plants has led to a new focus problem in the study of NOx formation and emission characteristics under off-design conditions. The difficulty in this study is due to the complex physical

The current paper studies the most suitable ultra-low-global warming potential (GWP) (GWP < 30) candidates in the market, considering also its grade of flammability and toxicity, for heat pumps employed for different space heating and domestic hot water (DHW) applications. A pre-design thermodynamic model has been developed to evaluate the performance and size limits for any subcritical or transcritical

In this paper, an artificial neural network (ANN) has been studied for the viscosity of MWCNTs-ZnO/water-ethylene glycol (80:20 vol.%) non-Newtonian nanofluid. To evaluate the rheological behavior of the nanocoolants, for each solid volume fraction and temperature, all experiments were repeated at different shear rates. After generating the experimental data, an ANN method is applied. The ANN is selected

The objective of the present study was to check the approaches of numerical simulation of a finned-tube oil radiator of power engineering devices, cooling systems of compressor stations, etc. The additional tasks were to define thermal and hydraulic characteristics of an oil radiator without field tests and to reveal possible design defects. In the course of the study, the obtained experimental data

Thermal insulation materials with micro/nano porous structure are widely used in aerospace field. Gas permeation has a marked impact on thermal insulation properties of insulation materials. Most investigations on gas permeation measurement are based on one-dimensional Darcy's law by measuring the pressure gradients and the volume flow of the two sides of the materials. However, the two-dimensional

The present scenario shows that the usages of electronics equipment are very extensive because of its performance and compactness. The concept of boiling heat transfer is applied to cool the equipment for better thermal management system. In the present experimental investigation, the copper substrates were coated by SiO2 and copper hybrid thin film by the radio frequency sputtering method. The thickness

Waste heat recovery system is a system using for preheating fresh air needed in industrial and waste heat plants. The aim of this study is to improve the performance of a heat recovery unit by using a heat exchanger consisting of a heat pipe which uses a (CuO + ZnO)/water hybrid nanofluid as a working fluid. As is known, the nanofluid in the heat pipe is able to evaporate at a temperature lower than

A model for the growth of a bubble on a horizontal heated surface with a constant temperature and in a subcooled condition is presented. The model considers microlayer evaporation, transient thermal boundary layer conduction, and surface condensation or evaporation. The bubble growth time is divided into several stages, and the equation describing the bubble growth is simplified for different stages

Development of renewable energy technology and improvement of energy efficiency have currently become necessary. In particular, active ultrasonic cavitation has attracted a great deal of attention in the enhancement of heat transfer efficiency, and this has been investigated in the current work using numerical methods. A physical model and associated simulation methods are first introduced. Next, the

In accordance with the early works of the authors, the modernization of the propellant charge is possible by using propellant like a traveling charge pushing a projectile in the barrel. The advantages of this technology are increase in the loading density and propellant mass, and therefore increase in the energy of the propellant. The use of this technology leads to the redistribution of the combustion

In recent decades, thermochemical heat storage has been considered as a promising candidate to make long-term storage and long-distance transportation of thermal energy possible. Especially, the thermochemical heat storage system Ca(OH)2/CaO is thought as one of the most potential thermochemical processes for storing middle- and high-temperature thermal energy. In this study, we have investigated the

Impinging-film cooling is a kind of hybrid cooling, in which the cooling effectiveness would be influenced by the impingement characteristics. Thus, this paper investigates the effects of impinging parameter variations on the performance of impinging-film cooling. The impinging parameters include jet inclination (30°, 45°, 60°, and 90°), jet-to-slab spacing (1 mm, 1.5 mm, and 2 mm), and jet hole diameter

In this investigation, turbulent forced convection nanofluid flow with water as base fluid, Al and Cu as nanoparticles over an inclined forward-facing step is numerically studied in detail. CFD simulations were performed for a heated forward-facing step channel with different step lengths, and different inclination angles of the step and flow Reynolds number with ranges of 20° ≤ θ ≤ 80° and 30,000

A three-dimensional coupled heat transfer model is applied for numerical studies of turbulent flow and heat transfer of methane in variable cross-section cooling channels of LOX/methane rocket engines at a supercritical pressure. The results indicate that when the coolant flows through an abruptly expanding structure, the fluid flow velocity suddenly drops, and the average temperature of the fluid

Unstable operations like temperature oscillation often occur in loop heat pipes (LHPs) and therefore restrict their applications. Such instability issues are strongly related to the LHP structure, heat load, working fluid, filling ratio, gravity acceleration, and other factors. The mechanism of temperature oscillation of LHP is studied both experimentally and theoretically by investigating the vapor-liquid

The thermal conductance in Nafion molecular chain is investigated by VASP, Phonopy, and ShengBTE based on the first-principle calculation. By using the mechanical structural analysis and chemical bond analysis of crystal orbital overlap population, the strength of carbon-carbon bond, carbon-oxygen bond, and carbon-sulfur bond is discussed. Combined with the pDOS (phonon density of state) analysis,

Two-dimensional numerical simulations of underwater vapor bubble on a hot spot have been performed to investigate the thermocapillary-driven flow generated at the bubble interface and the accompanying flow near the contact line. With fixing the bubble diameter of 10 μm, several contact angle and hot-spot temperatures have been considered to discuss the flow characteristics relevant to a mechanism of

The flow and thermal characteristics of the Marangoni convection (thermocapillary flow) around a microbubble are described in this study for the case in which a bubble is attached to a locally heated microchannel wall (hot spot applied). By providing a heat source near the bubble and generating a temperature gradient on the surface of the bubble, Marangoni convection can be produced in the surrounding

The thermal design of various engineering applications plays a prominent role in deciding the overall efficiency of the system. Nowadays, nanofluids have attracted the interest of researchers due to their excellent thermophysical properties. There were several researches emphasising the importance of two-phase materials and nanofluids in the effective thermal design, but none have attempted to integrate

The thermal and optical properties of layered structures of molybdenum disulfide (MoS2) were studied based on the first-principles density functional theory. The phonon density of states in various layered and bulk MoS2 shows a discontinuous band gap between about 7.0 and 8.0 THz. The specific heat variation with temperature and other thermodynamic properties like the Helmholtz free energy, entropy