Elastic turbulence has shown great potential to improve mixing and heat transfer performance. Most of the studies, however, are focused on the mixing behaviour, heat transfer characteristics induced by elastic turbulence are still not well established. This work investigates systematically the flow and heat transfer performance by elastic turbulence in a swirling flow region. The heat transfer enhancements

The condensing flow of R1234yf in a smooth horizontal helically coiled tube is studied experimentally to achieve the heat transfer coefficient and frictional pressure gradient. The helical coil diameter is 95.3 mm with a constant pitch of 16.7 mm and is made by coiling a flexible smooth tube with an internal diameter of 8.2 mm. The effect of vapor quality, mass velocity and saturation temperature on

During cold dynamic gas spray additive manufacturing, the thermal field within particles is generally simplified by a state of an instantaneous uniform distribution over the particle's media at any position inside and outside the De-Laval nozzle. This paper addresses critical discussions using analytical and computational analysis of the transient heat transfer within the solid particles due to the

This study numerically and experimentally investigates the transport phenomena in buoyancy-driven smoke inside stairwells in a high-rise building. Hot smoke is supplied at the bottom of a small-scale, 2-m high stairwell prototype, and the smoke velocity and temperature are measured and compared with the corresponding numerical results. For all-windows-closed cases, the Fire Dynamics Simulator (FDS)

The study gives a comprehensive overview of ferrohydrodynamic pipe flow experiments under the influence of magnetic fields carried out in the last decade. Both cases laminar and turbulent flow are considered. The compilation confirms that significant enhancement of heat transfer is possible as long as the magnetic field has the same orientation as the heat flux. Various effects, among them chain-like

This paper deals with a two dimensional Stefan problem of solidification in arbitrary bounded domains. To realize this, the governing equations are transformed from a complex physical domain to a simpler computational domain using body-fitted coordinates and the corresponding transformed equations are solved using an alternating direction implicit (ADI) method. Stability analysis of the proposed ADI

In the current study, free convection heat transfer of a suspension of Nano–Encapsulated Phase Change Materials (NEPCMs) is simulated and discussed in an inclined porous cavity. The phase change materials are capsulated in nano-shells layers, while the core stores/releases large amounts of energy during melting/solidification in the vicinity of the hot/cold walls. The governing equations are introduced

Microchannel evaporators are capable of removing large heat fluxes by taking advantage of the latent heat of phase-change. However, flow maldistribution in the parallel channels of the evaporator can cause a considerable variation in the cooling performance of each channel. Such variations in performance are undesirable and present a significant challenge to implement this strategy effectively. To

This work improves a layered thermal resistance (LTR) model for the prediction of phase change times in solid-liquid phase change heat transfer. A combination of analytical and numerical approaches is applied in 1-D and 2-D solidification problems where heat conduction is dominant. In the improved layered thermal resistance (ILTR) model, the domain is discretized to layers. Based on its thermal resistance

Understanding of moisture role and heat transfer in thermal insulation fabric was crucial for improving thermal protective performance of the fabric against hot surface contact. The hot contact tester was used to measure the heat transfer in “hot surface-fabric-skin simulant sensor”. Two new indexes were proposed for investigating the effect of moisture content on the transmitted and stored energy

Transpiration cooling using liquid coolant has been proven to be one of the most potential thermal protection techniques for hypersonic vehicles. However, the drastic pressure variation during phase change of liquid coolant may result in unsteady cooling effects, and this complicated problem has not been studied in detail, up to now. This paper presents the experimental investigation and theoretical

Herein, a net-based topology optimization approach for cooling channels is presented, which helps to make a balance between power dissipation, thermal stress and temperature limitation in forced internal cooling problems with approximate but fast and low-cost calculations. The topology optimization procedure consists of a discrete based flow and heat coupling analysis, the flow analysis by the improved

A numerical analysis has been performed on a real-scale infrared suppression device to estimate the air entrainment and corresponding temperature drop of the exhaust gases flowing through it. The analysis of the IRS device is done for the exhaust of a gas turbine plant installed on a naval warship. The operational data used in the analysis has been taken from LM2500 series gas turbine from GE. The

In the present work, an interferometric unsteady analysis of the thermogravitational technique was for the first time attempted in a paralelepipedic microcolumn using binary mixtures with negative Soret coefficients. In particular, water/ethanol and toluene/methanol were considered, as they have significantly different thermophysical properties and relaxation times. Experiments were run with different

Hot fluid pockets or hot spots can be found in many engineering systems, such as chemical reactors, internal heat engines and gas turbines. They are inherently fluid parcels with rapid temperature rising in comparison with the base medium and usually convect with the flow inertia. Due to the higher energy content, hot fluid pockets can change thermal characteristics of the system. Ignoring the destruction

A comprehensive analysis of 6-published and 15-new Kersten (Ke) functions, i.e. normalized soil thermal conductivity (λ) expressions, was conducted using a complete λ data base of 40 Canadian soils. It was confirmed that Ke depended mainly on the degree of soil saturation (Sr), while additional dependency on volumetric content of sand (θsa) as the second variable Ke(Sr,θsa) and organic matter (θo-m)

Influence of gas radiation on a thermal plume initiated by a linear heat source in a confined cavity is investigated through numerical simulations. A 2D pure convection case is first considered to validate the numerical code by comparing the critical Rayleigh number against literature results. Then, simulations are extended to 3D configurations for three different values of the Rayleigh number: 106

This paper explores the performance effects of a novel small-scale multiple vortex generators (MVG) on heat transfer deterioration (HTD) mitigation and pressure drop using supercritical CO2 (sCO2) as the working fluid. The HTD mitigation and pressure drop are examined using an overall performance factor, R = ΔHTD/(Δp/Δp0). Numerical calculations are first conducted to investigate the effects of single

Flame propagation behavior over the polymer insulation of electrical wires can ignite adjacent combustibles and increase the scale of the fire. In this study, the flame propagation behavior over polyethylene (PE)-insulated wires was investigated theoretically and experimentally under varying pressures. The experiments were conducted in three cities with different altitudes (64, 76, and 100 kPa) and

The flow over a topography or a step is a fundamental problem in fluid dynamics with relevance to many fields and circumstances. In the present analysis direct numerical simulation (DNS) is used to examine the properties of the thermofluid-dynamic field in a square cavity with a heated obstruction located on the bottom. The involved dynamics include forced flow driven by injection of cold fluid through

Experimental results of isothermal pressure drop and convective heat transfer coefficient are presented for a smooth tube with tri-orifice baffle inserts, under net and oscillatory flow conditions. Using propylene-glycol as working fluid, net Reynolds numbers in the range Ren=10−600 are reproduced, allowing to describe Fanning friction factor in the laminar, transitional and turbulent regimes, with

Two-layer fluid flows with evaporation at the thermocapillary interface have been studied on the basis of the partially invariant solution of the convection equations. The modeling of the 3D fluid flows has been performed in an infinite channel of the rectangular cross section without assuming the axis-symmetrical character of the flows. The fluid flow patterns are determined by various thermal, mechanical

The flow characteristics and heat transfer performances of tube with ellipsoidal dimples are numerically investigated in this present work. Skewness and kurtosis of dimpled tube wall surface are calculated by discrete method. Effects of dimple cross section shape, number, cross distribution angle and pitch on thermal-hydraulic performance and roughness parameters are discussed. These results show that

A loop heat pipe (LHP) can effectively improve the heat dissipation capacity for a variety of equipment and instruments with high heat flux. A superhydrophilic porous wick was fabricated in a LHP to investigate the effect of wettability and nanostructures on heat transfer performance. These wicks can be achieved by copper powder sintering and surface modification through hydrogen peroxide (H2O2) oxidation

In the current study, heat transfer behavior in electrohydrodynamic conduction pumping of two different dielectric liquid films using flush electrodes has been experimentally studied, and effects of working temperature and fluid physical properties on heat transfer enhancement are investigated. The study is conducted for different liquid film thicknesses and working temperatures, while changing the

In this work, a microcellular model is developed to study the thermal behavior of a plate constituted of paraffin impregnated in metal foam. A three-dimensional model is considered using the finite elements method (FEM) with a body centered cubic (BCC) shape as a geometric configuration. COMSOL Multiphysics software is used to build the geometry and to conduct the calculation. The effects of porosity

In this paper, convective heat transfer of argon in a nanochannel is investigated by molecular dynamics method. Simulations are performed by LAMMPS code and the effects of wall material, wall roughness and nanochannel size on Nusselt number are studied. To study the wall material effects on convective heat transfer, argon, copper and platinum walls are considered. Results show that convective heat

Combined heat transfer mechanisms in open cavities is a relevant research topic because of its direct application in the design and thermal characterization of solar receivers'prototypes. These devices have several applications, for example, solar furnaces and solar tower systems where a central receiver is used to increase the temperature of a working fluid, which is then employed to produce electricity

The multi-phase flow characteristics and preferential paths in the heterogeneous pore structures of reservoir rocks at high pressures and temperatures are much significant to evaluate the exploitation efficiency of subsurface hydrocarbon resources and carbon sequestration effects. Therefore, these characteristics and paths should be accurately described and understood. However, only a few existing

The enhancement of airside heat transfer in fin-and-tube heat exchanger is crucial for reducing the pumping power, saving materials and so on. In this paper, the authors propose to arrange the winglets radiantly around the tubes on the fin to enhance the airside heat transfer in fin-and-tube heat exchanger. The airside flow and heat transfer characteristic are numerically investigated. The position

This study concerns with the effect of transverse vibration of an internal plate on mixed convection heat transfer inside a square enclosure of a glass recycling process dryer. The plate can oscillate in horizontal and vertical directions. The Reynolds-averaged Navier-Stokes equations are used to describe the unsteady turbulent flow field. The governing equations are solved numerically applying a finite-volume

Three different heat transfer augmentation techniques namely pin-fins, protrusions and dimples applied to the substrate of a pyramidal sandwich panel are investigated. The flow and heat transfer characteristics of the three modified panels are numerically analyzed and the results are compared with those of the base pyramidal sandwich panel with no surface modification. The heat transfer augmentation

This paper presents numerical studies of thermophoresis approach for separation of nanoparticles in liquid media. We simulated the thermophoresis process to test it as a method of separation of particles in suspension. At the same time, the specific software was appraised to establish whether it would meet the computational challenge. Then, a microfluidic device designed to separate different species

In order to investigate the flow and heat transfer characteristics in advanced vortex combustor(AVC), numerical analysis of multi-field synergy on combustion flow has been performed. The results show that the region with smaller field synergy angle β between velocity and temperature gradient is mainly distributed behind the blunt body, in the cavity and in inlet channel. The synergy degree between

In this study, we perform a numerical investigation to better comprehend the domination and the effect of strong thermal buoyancy on hydrodynamic and thermal characteristics, vortex shedding in particular, of a horizontal circular heated cylinder subject to a vertically upward laminar flow stream. The Reynolds number is varied in the range 20 ≤Re≤ 150 while maintaining the Prandtl number constant at

A parametric study of the flow field and mixing characteristics of a TiCl4 jet injected into an O2 crossflow in an oxidation reactor for titanium pigment production is numerically investigated. A three-dimensional computational fluid dynamics (CFD) simulation of the turbulent gas mixing model is performed. The effect of geometrical (reactor diameter, jet nozzle number n, jet nozzle diameter, jet nozzle

The main objective of the study was to present the Chilton-Colburn analogy in relation to mass and heat transfer processes occurring in minichannels. Because of the so-called scaling effects being in channels of small geometry the validation of the analogy between transfer processes in the case of convective fluid flow through the mninichannels seems to be necessary. The paper provides an overview

In present research, a CFD-based approach together with the validated finite volume N–S solver had been applied to precisely analyze the spill flame characteristics in adjacent space induced by fire incident in a Chemical Hazardous Materials (CHMs) container. Coupling mechanism between spill flame behavior and opening types of CHMs container was discussed in terms of different container vent sizes

In present work, a miniature rectangular groove (MRG) is arranged at the bottom of the rectangular channel, and an effective slip surface is constructed. The flow and heat transfer characteristics in the channel with MRG are numerically investigated by Large Eddy Simulation. The results show that the fluid flows over the spanwise vortices inside MRG rather than over the non-slip solid surface. Therefore

A novel integral equation method based on radiation distribution factor (RDFIEM) is developed for solving radiation transfer equation (RTE) to obtain radiation intensity signal in a small solid angle on a small point, which is effectively applied to reconstruct the three-dimensional (3D) temperature distribution in an absorbing, emitting and scattering medium. The spatial distribution of radiation

In this work, the effect of flow approach angle (α) on forced convective heat transfer from an elastically mounted vibrating rigid square cylinder is studied numerically. The Navier-Stokes equations along with the two-dimensional equation of motion of elastically mounted rigid square cylinder are solved using finite difference method. An Arbitrary Lagrangian Euler (ALE) method is used to capture the

The present study aims to investigate combined heat transfer by natural convection, conduction and surface radiation through double solid wall separated by an air layer. The outside vertical surface is submitted to an incident solar flux and outdoor environment temperature. The inside surface is submitted to indoor environment temperature. The radiative coefficient (hr), the convective coefficient

Starting from the data collected on six patients with various types of hematological diseases that have received a bone marrow transplant, this study investigates the onset of GVHD (Graft versus Host Disease). The disease is linked to bone marrow transplantation and is caused by the immune cells (white blood cells) of the donor that attack the recipient's tissues (host). This causes damage to different

The present paper discusses a new approach for predicting the nucleate boiling transfer coefficient based on the physics of nucleate boiling at atmospheric pressure under saturated conditions. Therefore, a non-dimensional correlation of the nucleate boiling heat transfer coefficient developed as a function of bubble departure diameter, active nucleation site density, and bubble departure frequency

The parameters used to specify the intensity of secondary flow in helical coiled tube and tubes with twisted tape insert can be obtained easily without knowing whole detail velocity field. It is found these parameters determine the characteristics of heat transfer and fluid flow. There are no parameters to specify the intensity of secondary flow in a twisted elliptical tube. Thus, this paper tried

Effects of insertion of a straight tape mounted with double-sided V-baffles used as a longitudinal vortex generator (LVG) on turbulent convection heat transfer behaviors in a constant heat-fluxed tube in the Reynolds number (Re) range of 4120 to 25,800 are experimentally and numerically investigated. In the present experiment, the V-baffles at a fixed attack angle (α = 30°) were placed on the tape

The present paper numerically investigates the laminar, two-dimensional and horizontal flow around a horizontal isothermal rotating cylinder under the buoyancy effect. To study the buoyancy effect, a range of Grashof numbers from 0 to 12 × 104 is used, and to check the effect of the cylinder rotation, the ratio of the rotational speed to the free-stream velocity between −4.5 and 4.5 is applied. The

The microstructural and mechanical properties of metal materials are affected by the cooling rate during the heat treatment. The temperature distribution and the corresponding cooling rate are determined by the heat transfer coefficient. To study the heat transfer coefficient of an advanced nickel-based superalloy during the end-quench process with air, the experimental and fluid-solid coupling numerical

In this study, a novel and innovative baffle design was offered in order to considerably reduce shell side pressure loss without compromising thermal performance. Computational fluid dynamics (CFD) was utilized to simulate and visualize 3-D turbulent flow field in the shell side so as to investigate various shapes of baffles for preliminary baffle design purposes. The simulation results showed that

An open capillary evaporator is proposed to study the evaporation heat transfer performance of porous wick. Both temperature and evaporating mass are measured in this system. Besides, the temperature and relative height of the supplied fluid can be adjusted. A composite porous wick is tested through the constant and variable heat load operation, and it reaches a maximum heat load of 320 W, which corresponds

Floatation nozzle is a key component for manufacturing high performance substrates in the roll to roll processes because it can support the substrate without contact. The heat transfer and pressure distribution of the floatation nozzle, which is highly associated with the flow dynamics, greatly affect drying/heating/cooling efficiency and operating costs of the nozzle. However, the flow dynamics and

Thermal conductivity of the Phase Change Materials (PCMs) of latent heat storage systems is enhanced by dispersing nanoparticles in base PCM for increased heat transfer rate. Heat transfer characteristics of the newly developed erythritol PCM dispersed with 1 wt% graphene nanoparticles in a newly designed shell and helical tube storage tank during charging and discharging processes was investigated

In the present work, Large Eddy Simulation (LES) is employed to investigate the heat transfer performance and flow characteristic in a rectangular channel with three-row miniature square column vortex generators (MSCVGs) as Reynolds number varies from 3745 to 11,235. The height of the MSCVGs is less than the thickness of the boundary layer, and MSCVGs arrays arranged in the form of aligned and staggered

Based on the thermal conduction and temperature uniformity of heat pipe and on the premise of ensuring the strength safety requirements of ventilated brake disc (VBD), transfer the heat of high temperature zone to low temperature zone timely by embedding heat pipes on the surfaces of VBD, and the heat transfer enhancement study of VBD during braking processes were developed. The brake bench test and

Natural convective circulation in a rotating porous chamber with an element of variable volumetric heat generation has been investigated numerically. Brinkman model has been employed for porous medium. Governing equations written using non-dimensional parameters have been worked out by the finite difference technique. The computational technique has been verified by comparison with results of other

In this study, the atmospheric plasma process (APP) was used to modify the surface of aluminum nitride (AlN) powder with different particle sizes and morphologies (non-spherical and spherical), using modified AlN powder as fillers for polydimethylsiloxane (PDMS) to form AlN/PDMS composites. The functional groups on the surface of the AlN powder, before and after APP modification of the AlN powder,