During the braking process it can be appeared many undesirable effects that can disturb the safety of all participants in the traffic. It can be considered 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 it will be investigated deeply the thermal and the stresses that appeared

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 both in liquid and vapor phase, 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. Theflow 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 scale inhibition mechanism of SCMC was revealed

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

The heat transfer and resistance performance in heat exchangers using symmetric corrugated tube, asymmetric corrugated tube, and helical corrugated tube are investigated experimentally. And numerical simulations are conducted to study the mechanism of thermodynamics and fluid flow. Then, the total heat transfer efficiency of heat exchangers using these tubes are analyzed, and optimal velocity matchings

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

The accuracy and adaptability of the structure model and numerical model were discussed scantly in the numerical calculation for the thermal power plant SCR system. Therefore, the characteristic structures on the accurate calculation of flue gas flow field, the method and rationality of parameters setting used in the porous medium model, the theory and rationality of parameters setting used in the

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

An integrated simulation method was proposed to investigate the NOx formation and removal processes of a 600 MW unit under off-design conditions systematically. The NOx formation process was carefully simulated, and the boiler thermodynamic calculation method was adopted to calculate the operation condition of the Selective Catalytic Reduction (SCR) device. Furthermore, a steady-state isothermal mathematical

Thermal insulation materials with micro-nano pore 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 diffusion

Thermochemical heat storage has obtained increasing attention in recent decades, which have been considered as a promising candidate to make long-term storage and long-distance transportation of thermal energy possible. The Ca(OH)2/CaO thermochemical heat storage system is thought of one of the most potential thermochemical processes for the storage of middle- and high-temperature thermal energy. In

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 thermal and optical properties of layered structures of molybdenum disulphide (MoS2) were studied based on the first-principles. The photon 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, and total energy are similar

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%

Closed form solutions are presented for the steady magnetohydrodynamic (MHD) buoyancy-driven convection flow, heat and mass transfer from a semi-infinite vertical surface with wall transpiration, first order chemical reaction, viscous heating, Ohmic heating and magnetic induction effects. Magnetic Reynolds number is large enough to permit the inclusion of magnetic induction effects. The governing boundary

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

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

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

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

In the present study, a thermochemical dissolution model based on the lattice Boltzmann method is proposed to investigate the reactive transport process involving immiscible fluid flow, mass transport, heat transfer, and dissolution. The flow of the two immiscible fluids, solute transport in the corresponding solvent, and heat transfer are solved by the Shan-Chen mul-ticomponent lattice Boltzmann model

Boiling and condensation, a kind of convective heat transfer characterized by high heat fluxes, are widely encountered in many engineering applications. Fluids are the main heat carriers in heat transfer applications, and hence performance of a thermal system is remarkably linked with the working fluid's thermophysical properties. In thermal systems, nanofluids have been embarked upon to use as a working

The condensation heat transfer characteristics of R290 (propane) in a horizontal smooth copper tube and a microfinned copper tube with an outside diameter of 5 mm were investigated experimentally to study the condensation heat transfer strengthening characteristics. The enhancement factor Sf was introduced to characterize the degree of strengthening condensation heat transfer of R290 in a microfinned

Refrigerators are one of the most frequently used household devices; therefore, they represent an interesting subject for investigations. One of these research topics is the condensation problem in the gasket region. Despite the use of heaters in the refrigerator door, condensation on the surface of the gasket may still occur. Thus, there is a need for an improved gasket structure to overcome the condensation

A comprehensive thermodynamic analysis of a refrigeration system with an internal heat exchanger was reported for four various refrigerants as an alternative to R134a. The preferred refrigerants in this paper have zero ozone-depleting potential and fairly low global warming potential value compared with reference R134a. These refrigerants are from both the HC group (R290 and R600a) and the HFO group

In this study, the effects of malfunctions and problems occurring in the system components of air handling units, which are the main elements of the air conditioning system, on the energy consumption were investigated. Investigations were carried out in 10 air handling units located in 5 different shopping centers of Turkey. The malfunctions and problems that may occur in operation of air handling

One of the significant issues in energy conversion systems is efficient heat transfer which is generally done by heat exchangers (HEs). Different ways have been utilized to increase the performance of HEs. One of these ways for enhancing heat transfer rate is using a nanofluid. In this experimental work, the effect of utilizing Al2O3-SiO2/deionized water hybrid nanofluid at various particle ratios

Biopreservation is the science of extending the shelf life (storage time) of biological systems. The scientific field of biopreservation can be broadly classified into three distinct but interrelated research areas: Cryopreservation (storage by freezing), Desiccation (storage by drying) and Freeze-Drying (storage by freezing first and then sublimating the frozen water). Although, both freeze-frying