Since the horizontal projection upon the building facade are widely used in vertical fire-induced thermal protection, this paper is focused on the temperature decay beneath a horizontal projection of spilled plumes from a compartment window. A series of 1:8 reduced scale experiments were carried out in a cubic compartment. The window dimensions as well as the total heat release rates were variable

Experimental and computational investigation is carried out to study heat transfer characteristics and to explain the underlying physics for the case of inclined free surface liquid jet impinging on a uniformly heated flat plate. Experimentally, four Reynolds number 17541, 26,311, 35,081, and 438,521 were considered while in the numerical study, Reynolds number of 17,541 and 26,311 were considered

Aerogel infused fibrous blankets have been regarded as one the most promising superinsulation materials for application of thermal subsystems with severe limitations in weight, volume, and thermal insulation efficiency in space missions. Aiming at accurate description of radiation transport within such multiscale, multicomponent composites with absorbing, emitting, and anisotropic scattering features

Experiments and numerical simulations have been conducted to reveal the detailed turbulent flow and heat transfer characteristics over the surfaces with spherical dimples with different edge schemes, including the sharp edge, the fully rounded edge and the upstream rounded edge. The dimples have the same depth-to-diameter ratio of hd/d = 0.2. Steady-state heat transfer experiments were carried out

This paper studies a two-phase loop thermosiphon as a potential cooling solution for thermal management of insulated gate bipolar transistors (IGBTs). Water-based two-phase thermosiphon is initially analyzed. The flow instabilities of the loop and impact of different parameters such as heat flux, valve control near the inlet, and static head in the reservoir on thermosiphon performance are investigated

Fouling is one of the customarily happened, fundamental and expensive problems in heat transfer systems. It causes the reduction in heat transfer performance of the heat exchangers, energy loss and also, damage to the apparatus. Effect of fluid flow rate on the salt deposition was complicated in the previous researches. In this paper, a comprehensive rigorous investigation was performed to make clear

Proper thermal management through an effective cooling mechanism is essential for improving the reliability of operation of various electronic devices. A number of cooling methods are available among which passive cooling by natural convection has been deemed appropriate since it has distinctive advantages over active cooling or forced convection like high reliability, low maintenance cost, energy

This paper reports the results of an investigation to solve the inverse problem of estimating the strengths of different strip heat sources embedded in a flat plate under laminar steady-state forced convection and by way of this propose a novel method to detect hot spots from remote measurements. A Bayesian framework is adopted to infer the strength of the heat sources from thermochromic liquid crystal

The effect of crossflow Reynolds number on the film cooling characteristics was investigated on low speed flat-plate facility. The film cooling performance was measured by transient liquid-crystal technique and the flow feature was obtained by numerical simulation. Two film hole cases, converging slot hole case and cylindrical hole case, were carried out at two crossflow Reynolds numbers, Rec = 50

The objective of this paper is to quantify the precision of a novel approach for computational heat transfer modeling based on spectral graph theory. Two benchmark heat transfer problems with planar boundaries, for which exact analytical solutions are available, are used to determine the precision of temperature predictions obtained from spectral graph, finite difference (one-dimensional), and finite

The thermal rectification of a conductive thermal diode made up of two phase-change materials, whose thermal conductivities significantly change within a narrow interval of temperatures, is theoretically studied and optimized. This is done by deriving analytical expressions for the temperature profiles, heat fluxes and rectification factor. An optimal rectification factor of 60% is obtained for a thermal

The paper studies convection in a horizontal annular gap filled with a magnetic fluid or gaseous oxygen under the influence of gravitational and magnetic forces. A current-carrying conductor and an external uniform magnetic field magnetizing an internal cylinder of a material with high magnetic permeability were considered as a source of a magnetic field. The influence of the shape of the inner cylinder

The interest in Phase Change Materials (PCMs) has been continuously growing, since they were identified as a suitable way to store large quantities of thermal energy. Despite many PCMs being available on the market, almost all present a relatively low thermal conductivity, which limits the efficiency and the convenience of their use inside Latent Thermal Energy Storage (LTES) units. This paper proposes

In this study, condensation heat transfer coefficients (HTCs) of refrigerant R-600a (iso-butane) over horizontal 3-Dimensional integral-fin tubes were determined at vapor temperature of 312 K with wall sub-cooling temperatures of 3–9 K under heat flux of 33–87 kW/m2. Further, our experimental results were validated by comparing them with modified Wilson plot technique. Modified Wilson plot technique

High thermal-conductivity coatings have garnered much attention in fields such as the automotive and aerospace industries. Commonly used filler-loaded coatings are limited either by the high viscosity of the coating paint or by the intrinsic properties of the filler. In this study, we used graphene as a high thermal conductivity filler to enhance the properties of paint used in the automotive industry

A comprehensive experimental and numerical simulated pool fire test is conducted on stainless steel composite metal foam (S–S CMF) panels and is reported in this study. The uncertainty assessments for the measured and calculated unexposed surface temperatures in the calibration and simulated pool fire tests on the S–S CMF specimens are also conducted and reported. This test procedure is designed to

The paper deals with the problem of unsteady convective heat transfer during instantaneous transition to film boiling over a flat vertical surface, when heat flux is suddenly switched on. This heat flux exceeds the critical value, which corresponds to the onset of the film boiling regime. As a result, instantaneous transition to film boiling takes place. To solve the problem, two sets of the initial

An experimental and numerical study was done to discover the effect of insertion of twisted tapes of decreased tapered configurations inside a tube on thermal and hydrodynamic fields. Constant heat flux was supplied to the tube surface and the working fluid was the air which was flowed with turbulent flow of 10000 ≤ Re ≤ 40000. RNG k-ε turbulent model was used. The obtained results showed that there

The self-assembled clusters of regularly positioned small droplets were observed for the first time in 2004 by Alexander Fedorets. The recent results on stabilization of droplet clusters enable the laboratory study of specific parameters of chemical and biochemical reactions in the microdroplets. However, the analysis of the cluster behavior under the action of external factors is also continued. Some

Inclusion of fins in phase change energy storage systems has been widely investigated for improving the rate of energy storage. Despite significant past experimental research in this direction, there is a lack of comprehensive theoretical models for fin-based enhancement in energy storage, particularly for cylindrical geometries. This is a considerably challenging, non-linear problem. This paper presents

A precise heat transfer simulation of a three-dimensional impinging jet porous heat sink is presented and is analyzed from thermodynamics vantage point under local thermal non-equilibrium condition. To increase the computational efficiency of the analysis, pore-scale modeling based on lattice Boltzmann method (LBM) is used inside the porous media (at a meso-scale), whilst finite volume method (FVM)

Thermal energy transfer between two materials with different thermal properties is due to not only the temperature difference of the two objects but also the discrepancy in thermal inertia between the two materials. In this study, composite materials, called syntactic foams, with low thermal inertia feature were introduced as a new type of thermal shield preventing skin burn. Some types of syntactic

A numerical study on convective mass transfer enhancement by a lateral sweep vortex generator (LSVG)-dimple combination is presented. Surface features that can generate secondary flow structures are widely used for overcoming the difficulties in the transport process encountered in high-speed flows. Unsteady, three dimensional, turbulent fluid flow and mass transfer has been simulated using an Advection

Numerical investigation of fluid flow and heat transfer characteristics of a full-scale Infrared suppression (IRS) device for ocean liners is carried out in the present study. The main objective of the work is to reduce the temperature of the turbine exhaust by incorporating the IRS device, which can be effectively used in stealth technology for naval ships. In this study, the IRS device having multiple

Wavy fins and vortex generators can separately enhance the thermal performance of heat exchangers. A novel combination of wavy fins and vortex generators is proposed in the present study to optimize the thermal performance of heat exchangers. The effects of the longitudinal vortices and attack angle of the vortex generators on the thermal performance of the novel combination are numerically studied

A novel tube insert, fluid exchanger inserts, is proposed and numerically investigated for enhancing convective heat transfer of laminar oil flow in a circular tube. Effects of parameters including diameter ratio and number of inserts on convective heat transfer performance are also investigated. In the present work, servotherm medium oil is selected as the working fluid. It is found that the heat

The present study focuses on the heat transfer enhancement in sudden expansion channel (SEC) which is to be employed as solar water collector using vortex generator (VG) at different angles of attack. Expansion ratio (ER) of SEC is ascribed as 2:1. The analysis of heat transfer enhancement is carried out for various aspect ratios (AR) of ∞, 8 and 6 of SEC. The angle of attack (β) of VG is varied from

Traditional finite element models are usually established based on specific structures to address the transient nonlinear heat transfer analysis; however, if the structure parameters change one has to reanalyze/rebuild the finite element models, resulting in a lot of additional computational cost. To address this problem, this work develops a generic grid refinement approach to improve the computational

Inductive heating asphalt pavement (IHAP) has been widely investigated as the functional pavement, and IHAP is heated by induction heating of randomly dispersed inductive material under alternating magnetic field. Due to the randomly dispersed heat sources in IHAP, it is easy to cause uneven temperature distribution, which is difficult to be described by the existing thermal calculation methods. To

In this study, the effects of elliptical and super-elliptical film holes on the adiabatic film cooling effectiveness under a density ratio of 2 and blowing ratios 0.5 and 1 are studied. Five different cases are designed by considering various length-to-width ratios and the baseline is the model with cylindrical film hole. The DES with the Realizable k-ε model is adopted for the five cases to investigate

This paper numerically investigates air entrapment behavior when a water droplet impacts on a solid substrate in the presence of ambient air. The dynamics of air entrapment is specifically described, in particular, retraction, contraction and toroid formation have been discussed. Volume-of-fluid method has been used in order to track the liquid-gas interface. The effect of surface wettability on the

Glass façade is gaining popularity in modern commercial buildings in recent several decades. The thermal stability of façade structural elements then becomes a great concern in building fire safety. To provide a guidance for glass façade fire protection, an experimental study on the vertical temperature distribution of window plume with apparent external flames was carried out. Experiments were performed

Intersecting cooling holes allow very high density heat exchangers to be implemented in the cooling systems of gas turbine blades. The pressure loss and heat transfer characteristics caused by the highly turbulent flow at intersections are poorly understood. These are characterised experimentally and numerically for a single intersection of two equal diameter holes at 90∘ or 60∘/120∘ angles of intersection

The numerical and experimental data of the helically coiled-twisted trilobal tube (HCTTT) heat exchanger are compared, the results present that, due to more intense secondary flow of the HCTTT caused by the superposition of overall twist and self-twist, region near the center of the HCTTT has higher turbulent kinetic energy, and the region near the wall of the HCTTT is with the better Field synergy

In this study fundamental models were used by considering heat and mass multiphase transport in a porous medium which was coupled with the intermittent microwave convective combination drying process. The models were validated by experimental data sourced from references, and independent analysis was conducted to select a suitable mesh and time step. Sensitivity analysis was performed using different

This experimental study is focused on a rectangular synthetic (zero-net-mass-flux) jet impinging on a wall. The working fluid is air. A novel variant of a synthetic jet actuator (SJA) is proposed. Following biomimetic principles, the actuator incorporates a nozzle in which the cross-sectional area periodically oscillates during the driven cycle. Two independent actuating systems are used to drive the

A series of experimental tests were conducted in a narrow obstructed channel to investigate the influence of obstacle distribution mode (unilateral and bilaterally symmetrical distribution) and obstacle aspect ratio (the width-to-height ratio in flame propagation direction) on vapor deflagration. Rectangular obstacles with different aspect ratios 0.9–2.1 were used. The flame propagation speed, flame

Channels with ribs/baffles are widely applied in thermal engineering applications such as heat exchangers, solar water/air heaters and gas turbine cooling. In the present work, inclined and transverse twisted-baffles (I-TBs/T-TBs) are developed for heat transfer enhancement in a channel. The effects of Reynolds number (Re = 4000, 8000, 12,000, 16,000 and 20,000) roughness pitch ratios (p/w = 4.0, 6

Due to the accumulation of residual gas, vacuum failure may occur in the annulus of evacuated collector tube in solar trough thermal power system, resulting in the changes of flow and heat transfer mechanism and characteristics. In this paper, based on the actual situation of solar radiation in summer of Chongqing, China, the flow and heat transfer characteristics of the annulus in slip regime were

The numerical investigation is conducted to probe the heat transfer performance and flow behavior in a channel having miniature cuboid vortex generators (MCVGs) at Reynolds number 7490. The MCVGs are immersed inside the viscous sublayer, the transition area and the logarithmic law area. The effects of MCVGs in different areas on turbulent coherent structures are deeply probed. The overall efficiency

Thermal radiation in pebble bed is very hard to compute accurately and efficiently since it occurs between the surfaces no matter how far they are. Herein, radiative heat flux and effective thermal conductivity were derived mathematically by a matrix model to present the thermal radiation between particles in pebble beds. For structured packing, the transient radiative heat transfer is proven to be

Non-intrusive field measurements in the wake region of a circular adiabatic cylinder fitted in a channel are reported. The top wall of the channel is subjected to constant heat flux while maintaining the bottom wall and the cylinder under adiabatic condition. The cylinder diameter has been varied to achieve three different blockage ratios (D/H) of 0.25, 0.38 and 0.5. Experiments are performed in the

This study aims to assess the natural convection heat transfer in a square cavity wherein the buoyancy-induced flow is generated by a thin flexible heater-plate inside the cavity. The vertical walls of the cavity are cold and the horizontal walls are adiabatic. The thin hot plate is assumed to be isothermal and fixed at an alterable point in the middle of the cavity with different inclination angles

In this study, the combined effect of nanostructure and inlet restrictor on reducing the instabilities during flow boiling in parallel microchannel heat sinks is investigated experimentally. Four types of microchannel heat sinks are considered; plain microchannel, microchannel with inlet restrictor, nanostructured microchannel, and nanostructured microchannel with inlet restrictor. Different flow regimes

Three-dimensional conjugate computations are conducted to investigate the flow and heat transfer characteristics of a double-wall cooling system with a novel hexagonal arrangement of film cooling holes. Under the same coolant flow rate, the heat transfer and cooling performance of angled holes in the hexagonal arrangement are investigated and compared with those in the counterparts with conventional

The effective thermal conductivity of two evacuated expanded perlite powders has been measured at temperatures between 295 K and 1073 K. Since conduction via the gas phase is suppressed, thermal transport occurs only via solid conduction and thermal radiation. Due to thermal contact resistances between the powder particles, solid conduction is very small and radiative heat transport dominates, especially

In actual practical situations, the evaporator fins of refrigeration and air-conditioning apparatuses may operate under dry, fully wet or partially wet conditions. Thus in the present study, the optimum design of an array of constructal fork shaped fins operating under partially wet conditions has been determined by using a linear variation of the humidity ratio of saturated air with the corresponding

The present work is guided by the Constructal theory to identify the best shapes for the cavity inserted in a cylindrical solid body with a constant heat generation rate. From the assertion that a system must evolve to persist in time, an evolution of the elemental (I-shaped) cavity to a tree-shaped cavity with two branches added to a single branch is proposed. With these modifications, two restrictions

Railway embankments in permafrost regions are often affected by serious thaw settlement diseases resulting from permafrost degradation. For this reason, a novel, asymmetric crushed-rock-based embankment (ACBE) structure was employed in the construction of the Qinghai-Tibet Railway in Beiluhe, China, in order to increase cooling capacity and protect the transverse thermal stability of the tracks. This

To improve the thermal performance of microchannel heat sinks, non-uniform wavy microchannels were designed and their heat and mass transfer performance were studied by a numerical method. The effects of the Reynolds number, Re, and the peak deviation position on the thermal-hydraulic performances of the microchannels were analyzed based on the performance evaluation criteria (PEC) and the principle

This study examines the momentum and heat transfer aspects of the laminar forced-convection induced by a pulsatile flow of power-law fluids past a heated circular cylinder by numerically solving the time-dependent momentum and energy equations over the ranges of dimensionless parameters as the cylinder Reynolds number based on the mean velocity (0.1 ≤ Re ≤ 40), Prandtl number (0.7 ≤ Pr ≤ 100), power-law

The present work addresses the numerical and experimental study of natural convection inside an asymmetrically heated open double vertical facade. Two heating cases were considered independently, the constant heat flux (Neumann condition) and the constant temperature (Dirichlet condition). The double facade has been modeled using a vertical two-dimensional channel with one wall being maintained at

The thermal behaviour of an electronic equipment box under transient conditions is investigated. The box consists of a cabinet designed to contain electronic devices (such as infrared and visible cameras, hyperspectral sensors, etc.) carried on UAV systems and thermal control has to be assured only for the short duration (15–20 min) of each flight. Experiments were performed by considering a single

The lubrication oil cooler is widely used in many industries. The lubrication oil is usually operated in a laminar state with Reynolds number less than 1000 due to its high viscosity characteristic. It is hard to augment the heat transfer performance of high viscosity fluids without obvious pressure drop. A lot of researches have been conducted on the shell-side heat transfer and fluid flow characteristics

The cooling performance of natural draft dry cooling towers (NDDCTs) would significantly be reduced when the ambient air is hot. To address this problem, the spray pre-cooling technology has been introduced to cool the inlet air of the tower. The effect of two-nozzle distance on the evaporative cooling performance will instruct the arrangement of multi-nozzle for industrial applications. This paper

The steady-state, one-dimensional, Cartesian coordinate, non-linear ordinary differential energy equation of heat conduction through a conical spine extended surface of a thermal conductivity temperature dependent property that is proposed by an available quadratic function of a computer fitted model of a published experimental data is solved analytically using Kirchhoff's transformation and numerically