Realizing perfect contact between any two surfaces is impossible due to the presence of microscopic irregularities in material surfaces. Therefore, for true thermal analysis of multiple components systems knowledge of thermal contact conductance (TCC) between two solid bodies is essential. Estimation of TCC for different applications has been carried out in this paper by inverse heat transfer technique

The thermal conductivities of the 3D carbon nanotubes (CNTs), CNT/epoxy resin (CNT/EP) composites, graphene/EP composites and CNT/graphene/EP composites are systematically investigated via mesoscopic simulations using smoothed particle hydrodynamics (SPH) and dissipative particle dynamics (DPD). The effects of the CNT length and overall mass density on the thermal conductivity of the CNTs are discussed

The features of flow fluid and convective heat transfer have been investigated numerically in a rotating rectangular U-shaped microchannel for various aspect ratios (AR). Pure water is used as working fluid and 3D steady simulations are performed for Reynolds number of 400. The effects of aspect ratio (AR = 0.25–4), slip/no-slip conditions, rotational speeds in the range of 0–300 rad/s on the velocity

The liquid-metal cooled fast reactor is known as one of the most promising Gen-IV nuclear power system due to its high safety and superior economy. However, the turbulent heat transfer behaviors of low-Prandtl-number liquid metal in fast reactors are quite different from that of ordinary fluids due to its violation in Reynolds analogy, and there is still lack of a unified turbulent-Prandtl-number (Prt)

Thermal insulation materials are widely used in the fields of thermal protection and the energy conservation at high temperature. Thermal conductivity is one of the most important parameters of characterizing the thermal insulation performance of thermal protection materials. Steady state method such as the guarded hot plate method is normally considered as the most accurate method to measure the thermal

A numerical study of the flow and heat transfer by natural convection and surface radiation in a tall partitioned cavity is performed in the present work. The left part (glazed cavity) is filled with air (Pr=0.71) while the right part is filled with water (Pr=7). The two cavities are separated by a thin, rigid partition absorbing a solar flux S ranging from 0 to 1000W/m². The right (inner) surface

Enhancing the performance of heat transfer fluids (HTF) is a key target for improving the efficiency of many industrial processes. Employing nanofluids for this purpose, by dispersing nanoparticles into the initial HTF to improve its thermo-physical properties, is one possible way to increase its heat transfer capacity. However, testing these properties at high temperature is not always easy. An experimental

This paper investigated the effect of separation distance on the flame appearance and radiation heat flux of medium-scale pool fires dominated by radiation. A series of experiments were conducted on two adjacent heptane pool fires with diameters of 20 cm, 40 cm and 60 cm at separation distances ranging from 0 to 60 cm. According to experimental results, flame height and flame inclination angle increase

Impingement cooling is an important turbine blades cooling technique, but it is often not as efficient as required due to the deflection of downstream jets caused by crossflow. In this paper, a novel corrugated target surface is proposed to convert downstream oblique impingement into orthogonal impingement for higher heat transfer. To prove this design, the flow and heat transfer characteristics of

A local calculation method, based on the crystallization fouling model, is proposed to simulate the fouling process. Calcium carbonate crystallization fouling process occurring in a rectangular channel, with and without a vortex generator, is simulated by the integral and local calculation methods. The local calculation method is verified against the experimental data from the relevant literature.

Laser butt welding experiments assisted with high speed imaging were conducted to isochronously observe the keyhole and weld pool in this study. The time-averaged characteristics of the keyhole and weld pool geometries were extracted by image processing. The characteristics contained the upper width, bottom width and upper length of the weld pool, and the diameter and inclining angle of the keyhole

Film cooling is an important cooling method to protect the hot components in aero-engines and it is a classical research topic for decades. However, accurate simulation of the film cooling is still challenging. The present study aims to study film cooling with a newly developed Very-Large Eddy Simulation (VLES) method. State-of-the-art turbulence modelling methods are also included for comprehensive

Although many experimental and numerical studies on thermal convection exist for turbulent transpiration boundary layer flows on a porous structure, the general convective heat flux formula is urgently needed to clarify the influence of injection or suction on the energy transfer mechanism of turbulent heat convection. The two-dimensional (2D) theoretical convective heat flux structure obtained previously

The paper deals with the problems of describing heat transfer modes in a turbulent flow of supercritical water based on generalization of known experimental data for vertical round tubes. Due to the danger of overheating of heat transfer surfaces, special attention is paid to modes with deteriorated heat transfer. Later, the authors developed a universal model that includes the well-known Dittus–Boelter

The core material contributes ≥40% of the total cost of a fumed silica based vacuum insulation panel (VIP). Expanded perlites, which come at approximately one-tenth of the current price of fumed silica, have been identified as potential core material candidates. Though, the characteristic vacuum insulation properties i.e. evacuated thermal conductivity and half pressure value of expanded perlites are

The physical principles of magnetic hyperthermia are based on the heat generation of magnetic nanoparticles under the influence of applied magnetic fields of different configurations. The choice of a suitable methodology for generating a magnetic field can significantly affect the resulting thermal effect and thus the efficiency itself. The technical details of the apparatus generating a rotating magnetic

Since there exists few effective fire detection technologies for underground pipe gallery application, a temperature data-driven bio-inspired artificial intelligence algorithm is developed to detect fire source in 3D space of the underground pipe gallery, in which a simple physical model is used. In the developed algorithm, Ant colony optimization (ACO) is the first time to be used to determine tunnel

The performance of MWCNT + Fe3O4/water hybrid nanofluids as the coolant of a plate heat exchanger is experimentally investigated for particle concentrations in the range from 0.05 to 0.3 vol % and for coolant flow rate from 3 to 7 lit/min. The hybrid MWCNT + Fe3O4 nanoparticles were prepared by the chemical precipitation method and characterized with XRD, SEM, Raman, and VSM techniques. The thermal

A novel heat transfer device for narrow space was proposed to meet high power battery heat dissipation. Based on the battery heat generation data, the heat transfer enhancement mechanism of the secondary flow pattern is studied. Then establish the general heat transfer correlation for this liquid-cooled structure with a specific aspect ratio. The results show that the channel with rib angle of 90°

In this study, we performed a thermal simulation analysis of a space instrument, a solar spectrometer. A thermal model updating method was used to introduce the Kriging model as the surrogated model into optimizing thermal design parameters instead of directly iterating the finite element analysis. The sensitivity analysis method was used to eliminate the insensitive parameters, thus determining the

A novel thermal management system including wavy/stair channel liquid cooling and copper sheath is developed and studied experimentally in this investigation to control the temperature of cylindrical lithium-ion batteries. The influences of different variables on cooling performance during charge/discharge operations are investigated: C-rate, alumina nanoparticle concentration, inflow velocity, and

In this paper, a curved wavy channel was proposed to further enhance the thermal performance of the conventional wavy channel. A three-dimensional model of the curved wavy channel was established with defining the overall curvature. The flow behavior and heat transfer in the wavy and curved wavy channels were numerically investigated under various wave amplitudes. The mechanism behind the observed

Membrane-based absorption heat pumps (MAHP) operate based on the working principle of the absorption refrigeration system (ARS), which could be used to recover and transform low-temperature waste heat into useable heat sources with higher temperatures. This work focuses on the performance study of a counter-flow parallel-plate membrane-based absorption heat pump (PMAHP) to recover low-temperature waste

Air is considered as the feasible internal coolant to cool the vane of the gas turbines for the conventional cooling method all the time. However, the traditional cooling method gradually is difficult to meet the demand of increasing inlet temperature for the high-pressure turbine. Because of the excellent heat transfer performance of liquid metal, the scheme of liquid metal cooling gas turbine is

High heat transfer rate is essential in several industrial applications, including, nuclear reactors, storage and transport of cryogenic liquid, and metal forming, which deal with the rapid cooling of various materials. Rapid cooling of surfaces at temperatures significantly higher than the boiling point of the coolant is often restricted by formation of a vapor layer around the surface that retards

Quartet structure generation set (QSGS) method is improved to numerically reconstruct three-dimensional heterogeneous porous wicks with uniform pore size distribution. The capillary pumping processes of the reconstructed random porous wicks are simulated at pore scale by using a three-dimensional two-phase lattice Boltzmann model. The evolutions of two-phase interface and the variations of the imbibed

In this numerical investigation, the flow behavior, pressure drop, and heat transfer enhancement for the fluid in a corrugated pipe with varying geometrical configurations arrangements by supporting the computational simulation technique are analyzed. Also, correlations expressions for friction factor (f) and Nusselt number (Nu) with different corrugated geometrical parameters are developed. The numerical

Most of the available approaches for the prediction of effective thermal conductivity of composites are proposed for two-phase cases with inhomogeneities of simple geometry. Here, a procedure originally developed for two-phase composites is extended to obtain effective thermal conductivities of periodic composites with an arbitrary number of phases and geometric shapes of the inhomogeneities. The procedure

Unsteady numerical analysis is conducted for horizontal 16-channel rectangular-fin heat sinks with heat sink length of L = 127 mm. Beside normal heat sinks, those with guard-fin blocks at both sides as in the experiments of Harahap and McManus (1967) and Harahap and Setio (2001) are also studied to clarify the effects of guard-fin blocks on the flow characteristics and heat transfer performance as

This paper presents the heat and mass transfer model of a liquid droplet in the consistently changing condensation, transit and equilibrium evaporation regimes, and iterative scheme of numerical simulation of the instantaneous temperature of a semi-transparent droplet in the case of complex radiative-convective heating. The whole cycle of the phase transition regimes of medium and large water droplets

The sealing problem of flash vaporization equipment interferes with the flash evaporation process and reduces flash evaporation equipment's operating efficiency, wasting energy. This issue has not been given sufficient attention. The influence of air inflow rate on low-pressure static flash evaporation is studied by adding an intake valve on the flash chamber in experiments. The suitable adjustment

Interfacial thermal transport property between graphene and semiconductor is an important factor affecting heat dissipation of graphene based semiconductor devices. Here, we investigate thermal transport across graphene/Si and graphene/SiC interfaces using reverse non-equilibrium molecular dynamics simulations, and phonon vibrational density of states are calculated to reveal the mechanism of enhancement

The present study deals with the experimental and numerical investigation of steady combined laminar mixed convection and surface radiation heat transfer in the air-filled enclosure subjected to a constant heat flux supplied to the vent side of the cavity. Experimental results are presented for heat inputs, Q = 3.19 W–16.71 W, Reynolds number, Re = 4814–166385, and Richardson number, Ri = 0.1–25. In

Numerical simulations are conducted for steady flow striking a porous circular cylinder from various orientations in the mixed convection regime over wide ranges of the Reynolds number (5 ≤ Re ≤ 40), Darcy number (10−6 ≤ Da ≤ 10−2), and Richardson number (0 ≤ Ri < 7). The free-stream orientation is defined as an angle (α) between the directions of the free stream and the gravitational acceleration

An analytical evaporation model for multi-component spherical and spheroidal drops, based on the analytical solution of the Stefan–Maxwell equations is proposed to study the multi-component steady diffusion in the gas phase. A comparison with the ‘classical’ approach based on the Fick’s law is reported for three families of liquid mixtures, namely alkanes, alcohols and water solutions of alcohols under

High power performance of battery modules requires maintaining lower operating temperature and dissipating large amount of heat generated from the chemical reaction inside the battery. The high heat generated causes increase the battery temperature which leads reduce the battery performance and life cycle. Therefore, an efficient cooling system in battery modules is needed to ensure the safe and long-lasting

A boiling two-phase flow heat transfer experimental system for ammonia in a horizontal smooth tube with an inner diameter of 3 mm was established. The purpose is to explore the characteristics of flow boiling and dryout phenomenon. The experimental conditions: heat flux density is 10–30 kW·m−2, the mass flux is 40–200 kg·m−2·s−1, the saturation temperature is −10–10 °C, and the range of vapor quality

The mid-infrared spectral range is critical for bio-sensing and gas detection. Existing methods for designing wavelength-selective absorbers involve two-dimensional (2D) and three-dimensional (3D) nanofabrication, which is exceedingly expensive, rendering these methods impracticable. The application of a plane multilayer configuration using Fabry–Perot (FP) resonance can help overcome these drawbacks

This paper presents an experimental and numerical investigation on the thermofluidic performance of 0.5–2.0 % of the volumetric concentration of Al2O3-water nanofluids through oblique fin heat sink microchannel (OFHS MC) in the Reynolds number range 100–300. In comparison, experiments were also performed using a straight channel heat sink microchannel (SCHS MC) of the same hydraulic diameter as the

A study mainly concerning the fire-induced maximum ceiling smoke temperature in T-shaped bifurcated channel-like structure was conducted. A series of model-scale fire tests and full-scale numerical simulations were performed to obtain the maximum ceiling smoke temperature with various heat release rates and branch widths. Results shown that the branch could affect plume entrainment flow in vicinity

In this study, microchannel heat sinks with symmetric and parallel wavy microchannels are studied in a wide range of Reynolds numbers from 50 to 700 via a three-dimensional fluid-solid conjugate model. The results show that the symmetric configuration yields higher Nusselt numbers than the parallel one, and it is especially true at higher Reynolds numbers and larger amplitude-to-wavelength ratios.

Condensation heat transfer has been widely studied for various applications such as power generation, water desalination, data centers, chemical and pharmaceutical syntheses, heating and air conditioning systems, and especially, the passive containment cooling system (PCCS) in nuclear power plants. The PCCS is designed to reduce the risk resulting from a loss of AC power or compounding human error

Owing to improvements in the quality of life, the importance of devices for controlling indoor temperatures is increasing. However, devices based on current technology cause environmental problems, and there has been a growing global awareness regarding the requirement of innovative changes in cooling systems. Among such systems, those based on evaporative cooling have been widely studied considering

The entropy generation of two immiscible fluids is investigated in a conjugate heat transfer system. The velocity and temperature fields are analytically obtained by solving the momentum and energy conservation equations. These analytical solutions are used to calculate the local and total entropy generation rates. Based on the entropy generation minimization (EGM), the total entropy generation of

Minichannels are a key technology that results in energy, space, material, and cost savings in shell and tube heat exchangers (STHEs) because they improve performance by increasing compactness and reducing the dimensions, volume, and mass, as well as the amount of working fluids used. This paper employed the Computational Fluid Dynamics (CFD) method to investigate the effect of minichannels on the

A three-dimensional numerical study is developed to investigate the heat and mass transfer in the vapour removal channels of a Loop Heat Pipe (LHP). The heat transfer governing equations and the Navier-Stokes equations are solved under steady-state conditions for two vapour removal channel configurations: when the channels are in the wick and when the channels are in the casing. The boundary conditions

Measurements of local heat transfer coefficients on the circumference of a circular tube, fitted with two modified versions of an already existing axially inline curved Vortex Generator (VG) element insert are reported in this study. Measurements for average pressure drop are also presented and the air was used as the working fluid. The first modified insert is manufactured with a pair of two VG elements

This study comprehensively investigates the thermal transport behavior of unidirectional hybrid composites (UHCs) by means of a micromechanical methodology. The constructional feature of the UHC is that the continuous carbon fibers are embedded in the graphene nano-platelets (GNPs)-modified epoxy resin. The influences of volume fraction, length, thickness, and alignment of GNPs, the interfacial thermal

Insoluble gas in water can remarkably affect the boiling heat transfer performance, which is of great practical importance for many applications. The effect of insoluble nitrogen gas on the boiling of water over copper surfaces with different temperature conditions is investigated through molecular dynamics simulations. Observations on the nanofilm boiling phenomena and insights into the fundamental

The paper presents an analytical and a numerical approach to studying the effectiveness of the cooling of a granular target by gaseous helium. The increase in the target temperature is caused by an impinging beam which deposits a very high power of 138 kW inside the limited volume of the target. A porous domain approach is used to model the flow of helium through the packed-bed target. An efficient

We calculate the near-field radiative heat transfer (NFRHT) between two charged metallic plates with an external electric field oriented perpendicular to the plates. The near-field radiative heat flux is discussed in detail for gold, silver, and copper plates. The results show that the NFRHT between the copper plates is the largest. Due to the coupling between electrostatic interactions and surface

Thermal conductivity of CNT/Al composites is considered to be an important property on composites design. However, the effect of microstructure on thermal conductivity has few been reported. In this study, a 3D multi-scale finite element model was developed to predict the effective thermal conductivity of CNT/Al composites, and the influences of CNT configuration, heat transfer direction, interfacial

This paper focuses on evaluating the effects of flow rate and temperature changes of hot and cold fluid flows in multistream multi-fluid plate-fin heat exchangers with a single-component two-phase flow in the middle heat exchanger. This three-fluid heat exchanger included three layers with offset strip and wavy fin configurations. In the adjacent heat exchanger with offset strip fins, hot and cold

Fire spread between informal settlement dwellings (ISD) is a primary concern for large scale informal settlements conflagrations. Globally, approximately one billion people live in informal settlements and are exposed to these fires. This paper presents a fire spread experiment between two dwellings, built with ISO 9705 dimension as an approximation of an ISD and separated by 1 m. The fire development

The supersonic nozzle is very often used in many technical applications, such as fluid-flow machines or devices. If the medium flowing through a supersonic nozzle is a moist gas, moist air or wet steam, non-equilibrium condensation must occur. Such mediums usually contain impurities which affect the condensation phenomenon. The main purpose of this research is a numerical study on the effect of the

In the most common method of fresco painting, a unique integration of paint and plaster allows for frescos to acquire great durability and permanence. As the plaster or layers of fresco walls deteriorate over time, frescos become vulnerable to serious damage. In order to prevent such damage without harming frescos, non-destructive techniques must be used to analyze and determine areas of structure

Electrical wire is one of the primary causes of electrical fires because of short circuiting or overload current. Experiments were carried out to characterize the influence of high currents on flame spread and dripping behaviors over wires. Two samples of polyethylene (PE)-insulated copper wires with different sizes (dc/do = 0.9 mm/3.0 mm for wire #1 and 1.3 mm/4.2 mm for wire #2) were electrified

The effects of using convergent, convergent-divergent and divergent conical wire coils in ethylene glycol and water mixture flow region on the augmentation of heat transfer are experimentally analyzed. Three different volumetric ratios (0:100), (20:80) and (40:60) of ethylene glycol and water, convergent, convergent-divergent and divergent conical wire coils with two different pitch ratios 2 and 3