ABSTRACT The local heat transfer characteristics of circular multiple air jet impingement on semicircular concave surface were studied experimentally. For constant Reynolds number (Re = 9,000), the effect of jet to concave surface spacing (z/d = 1, 4.2, 6), ratio of curvature (D/d = 4.28, 6, 8.6), jet-to-jet spacing (s/d = 2.4, 4, 5.6), and number of jets were considered. The local heat transfer characteristics

ABSTRACT This study explores the performance of a steady-state flow single-phase non-conductive liquid immersion cooling system in a single-cell Li-ion battery under a variety of thermal environments such as 25°C, 40°C, and 60°C and tested at different charge C-rates. The experimental results show that the proposed cooling system exhibited the best cooling performance of less than 5°C and a significant

ABSTRACT Based on experimental and numerical studies the present work proposes an effective injection configuration for film cooling applications on sinusoidal corrugated surfaces. The experimental study is performed for different double-row injection locations (per wavelength) viz. (L0-L25), (L0-L50), (L0-L75), (L25-L50), (L25-L75) and (L50-L75) on the sinusoidal corrugated surface at blowing ratio

ABSTRACT A comprehensive understanding of the heat transfer mechanism of hydronically-heated structures is crucial to predicting their heating performance. However, few studies considered the heat transfer at the interface of heating pipe and host material. In this paper, heat transfer at two critical interfaces for hydronically-heated concrete structures, e.g. pipe-concrete interface and concrete-air

ABSTRACT An intermittent spray cooling system is applied to fuel cell vehicle heat dissipation using a plate-fin heat exchanger. The effects of various system parameters on cooling performances are evaluated. Experimental results indicate that the cooling performance can be increased by 20% to 80% at various operating conditions and fixed spray area percentage of 45%. An empirical correlation is constructed

ABSTRACT Direct absorption solar collectors (DASCs) typically achieve high efficiency due to the volumetric heat absorption process facilitated by the working fluids. In this study, carbon black (CB) nanofluids were utilized as the working fluid to experimentally and numerically investigate the thermal performance of a rectangular DASC. The findings suggest that the nanoparticles have the potential

ABSTRACT To verify the anisotropic effect on the thermal properties of hen egg white lysozyme crystals, we measured the thermal conductivity and thermal diffusivity of lysozyme crystals, the c-axis of which was magnetically oriented along the wire direction. We used the transient short hot-wire method in a horizontally tilted superconducting magnet bore. The crystals were magnetically levitated at

ABSTRACT This paper presents an experimental inverse approach to simultaneously estimate the temperature-dependent thermal properties of AISI 316 stainless steel. The heat flux conducted to the sample was corrected by using a transducer, evaluating contact resistance at microscopic level, and performing experiments under vacuum. Estimates were severely biased when heat flux correction was not applied

ABSTRACT The solar air heater (SAH), which utilizes solar energy to satisfy the building’s heating demands, is an important integrated component of the building. However, SAH’s performance isn’t good enough for it to be used in building. Adding roughness component to the effective zone of heat transfer underneath the absorber plate is the most successful and efficient technique to augment the thermal

ABSTRACT Flow boiling heat transfer is a promising technology for thermal management. In this paper, flow boiling heat transfer characteristics in a rectangular vertical flow channel are experimentally and numerically investigated at low flow rate. Visualization results provide guidance for the prediction of flow patterns. The flow boiling correlation at low flow rates is improved with an error of

ABSTRACT The continued depreciation of electronic components presents severe challenges for thermal management. Regarding this issue, the current experimental study targets to propose and assess two passive cooling (using a heat sink and rough surface) and two active cooling (air and water cooling) for improving the cooling efficiency of aluminum heat sink heat pipes (HSHPs). In roughening process

ABSTRACT The Particle Image Velocity method was used to investigate the velocity fields when the liquid layer height changed from 0.6 to 5.1 mm. The loss of stability of the velocity field during local heating is realized at the Bond number (Bo) 0.01–0.02, which is 10–20 times lower than the critical value of Bo(cr) compared to heat exchange at a uniform wall temperature. The Marangoni flow depends

ABSTRACT The current paper reports the impact of variation of ribs’ pitch distance in the case of laminar flow and forced convection heat transfer upon flow characteristics in a rectangular channel experimentally and numerically. The thermal behavior of the ribbed channel with water as a working fluid was measured experimentally and compared to numerical simulations performed using Galerkin finite

ABSTRACT Increasing processing capacity without modifying the size of electronic devices has made thermal management important in the electronic industry. Commercialized thermal management, such as in a conventional air cooling system, is insufficient for electronic devices with high heat flux dissipation. Pool boiling is a better method for heat transfer because it can dissipate a substantial amount

ABSTRACT Lithium orthosilicate has the highest absorption capacity among other materials used to capture carbon dioxide (CO2) at a higher temperature. To design a CO2 adsorption system consisting of lithium orthosilicate pebble bed, effective thermal conductivity and heat transfer coefficient data are necessary, and till date, these are not reported in the literature. In the present study, experiments

ABSTRACT In order to have a heat transfer per volume, heat exchangers have to have high overall heat coefficient. The effects of a transverse wedge on the heat transfer, the pressure drop, and the thermal efficiency factor (TEF) of air flow through a tube bundle heat exchanger was investigated. TEF increases continuously with the wedge aspect ratio (α). Form α = 0.275, 0.550, 0.758 to 1, TEF increases

ABSTRACT Micro heat exchangers are characterized by their high surface-to-volume ratio of up to 100,000 m2/m3. Due to superior heat transfer performance, their utilization for pure fluids is gaining increased attention. One major drawback though is the unwanted deposition on their surfaces when subject to fluids which tend to foul. To address this, a better understanding of the deposition process in

ABSTRACT The present study reports experimental investigations on jet impingement parameters such as nozzle shape, nozzle-plate spacing, Reynolds number, and effect of angle of cut for inclined nozzles on heat transfer. It is observed that the stagnation Nusselt number decreases with an increase in the angle of cut for inclined nozzles. Inclined nozzles produced a higher Nusselt number in the transition

ABSTRACT The temperature of melt blowing (MB) and melt spun fibers is frequently measured using infrared thermography (IRT). However, measurements are affected by the size and curvature of the fiber and by reflected radiation from the nozzle. A procedure was developed to obtain accurate measurements of fiber temperature, which corrects fiber size, fiber curvature, and reflected radiation. This procedure

ABSTRACT A numerical investigation for a solar air heater integrated with a multi-section solar distiller has been conducted with a novel design of solar distiller with interior sections. A mathematical description of the solar distiller is made and solved with a MATLAB code. The air flow in the solar air heater, the water height in the solar distiller, and the number of interior sections have all

ABSTRACT The work focuses on developing a detailed understanding of the effects of initial composition (Cin) and bottom cooling temperatures (TB) on different characteristics of double-diffusive convection during unidirectional solidification of water-NH4Cl solution in a complete non-intrusive manner. The qualitative investigation, simultaneous quantification of transported parameters (composition

ABSTRACT The electrochemical technique was used to investigate the effect of surface corrugations on the rate of mass and heat transfer (by analogy) in a stirred tank reactor. Impeller rotational speed, impeller shape, corrugation peak to valley height, and corrugation orientation (horizontal or vertical) were among the variables investigated. Depending on the operating conditions, surface corrugation

ABSTRACT The novelty of microencapsulated phase change material slurry (MPCMS) in the microchannel is a proven technique for enhancing the heat transfer due to its combination of high latent heat transfer and surface area. In this experimental investigation, the paraffin is encapsulated with silica and titanium shells, and its thermal performance is compared with three different configurations like

ABSTRACT Combined with visualization experiments, a square cavity reciprocating oscillation system is built based on CA6110 diesel engine to study heat transfer enhancement mechanism and explore a more efficient cooling method. Influences of liquid fill ratio, engine speed, and surface property on flow pattern and heat transfer characteristics are studied. Four surfaces are prepared. Results show that

ABSTRACT In this study, heat transfer behavior in a channel adapted with a set of equilateral triangular prisms was investigated experimentally in a turbulent flow regime, with a range of Reynolds numbers corresponding to 1x104

ABSTRACT The influence of metal foam thickness on the convection and conduction heat transfer is studied by measuring the local heat transfer of a smooth flat plate, attached and detached metal foamed flat plate under multiple jet impingement conditions. 27 jets of 3 mm diameter are introduced from a jet plate. These jets impinge on a thin stainless steel foil that serves as a targeted plate. The pitch

ABSTRACT In the present experimental study, heat transfer enhancement and friction factor penalty of a solar air heater (SAH) with newly designed artificial roughness attached to the lower side of the absorber plate have been investigated. Multiple open trapezoidal ribs artificial roughness has been designed to take the advantages of secondary flows concerning heat transfer enhancement. Multiple open

ABSTRACT Convection across circular concentric gaps between cylinders is crucial in industrial applications, including electronic cooling, heat exchangers, and solar collectors. The effect of longitudinal and annular grooves on the outside surface of the inside tube on natural convective heat transmission in enclosure concentric circular annulus is experimentally investigated in the present work. Twin

ABSTRACT In this work, an experimental investigation is performed to study the flame height and air entrainment of 0.2 m n-heptane double pool fires (DPF) with various separation distances (S). The results show an inverse relationship between the flame height and air entrainment with S. The increase in the flame height of DPF with a decrease in the air entrainment is more than half of the standalone

ABSTRACT The use of nanofluids for convectional heat transfer has become a spry area of research in recent years with the aim of improving heat transfer efficiency. Hybrid nanofluids have attracted significant attention and are advancing research and industrial applications since they involve employing more than one type of nanoparticle(s) in a base fluid. They enhance heat transfer by combining the

ABSTRACT The present study proposes a suitable injection configuration and operating parameters for the film cooling of an aero-engine afterburner, based on experimental and numerical studies. The experimental investigations are carried out for different injection locations for blowing ratios 0.5 and 1, fixed injection angle (45°), and density ratio (1.095). The numerical study is extended for various

ABSTRACT Heat transfer coefficient measurements for jet impingement onto the concave surface of a cone with apex angles equal to 30° and 70° are reported in this study. Static pressure measurements along the cone surface are also reported which aid in explaining the results from the heat transfer measurements. The conical geometry finds application for the heating of aircraft gas turbine engine nose

ABSTRACT In this paper, flow resistance and convective heat transfer of Al-kerosene nanofuels are studied experimentally. Al-kerosene nanofuels with mass fractions of 0.5 , 1 , and 2 g/L are prepared and applied as the flow medium for flow and heat transfer experiment via a heating facility. The experiment results indicate that the addition of aluminum nanoparticles has significant influence on both

ABSTRACT This study investigates the thermohydraulic characteristics of immiscible two-phase downward flow and heat transfer through porous media in a vertical, cylindrical, and homogeneous porous medium numerically and experimentally. The test section is exposed to a constant wall temperature after filled with spherical beads. Numerical solution of the model is achieved by the finite volume method

ABSTRACT In this paper, six different shape obstacles, namely, Isosceles trapezoid (Type 1), Triangular with curve apex (Type 2), Rectangular with chamfered edges (Type 3), Rectangular with curve edges (Type 4), Triangular with curve corner at bottom (Type 5) and Triangular shape (Type 6) have been tested in inline and staggered fashions in solar air heater (SAH) duct. This work aims to investigate

ABSTRACT An active method for heat transfer enhancement is proposed and thoroughly characterized for the first time for cryogenic quenching, in which mechanical vibrations are directly induced onto the sample to be quenched, employing a compact modular system composed of a pneumatic plunging device along with a DC motor/eccentric cam mechanism, generating oscillations on three different axes at a wide

ABSTRACT The present experimental study reports the flow and heat transfer characteristics of a synthetic jet issuing from a sharp-edged orifice (diverging-shaped orifice). The experiments are carried out for a varied range of opening angles of sharp-edged orifices (θ = 0°, 30°, 60°, 90°, and 120°), Reynolds number (Re = 3243–8143), different jet-to-surface spacings (z/d = 1–16), and for two different

ABSTRACT The performance of a solar air heater roughened with sine wave baffles has been calculated in terms of effective and thermal efficiency. Relative baffle length ( Lb/LP), relative roughness pitch Pst/e, relative height e/H, angle of attack (α∘), Reynolds number Re, Insolation I and Temperature rise parameter ΔT/I are the operational parameters. The sine wave roughened solar air heater has a

ABSTRACT This study prepares an experimental examination of thermal and hydraulic analysis of an absorber plate integrated with different arrangements of twisted turbulators, including longitudinal, transversal, and oblique orientations. These arrangements are considered for both the integral and the interrupted turbulators over Reynolds number range from 9174 to 55048. Nu ratio and f ratio range from

ABSTRACT In this study, the uniformity factor of the temperature difference field was introduced into the direct contact heat exchanger by establishing a trace element layer model for the heat exchanger. Furthermore, the uniformities of the temperature and temperature difference field of the direct contact heat exchanger operated using a continuous heat source were analyzed. The heat exchange height

ABSTRACT An experimental investigation of the effect of random vibration on the melting behavior of a phase change material (PCM) and the thermal performance of a PCM-based heat sink is presented. While random vibration from 2 to 16 g rms for the frequency range from 15 to 2000 Hz was applied to a rectangular enclosure, which contains paraffin wax and the heat sink, a constant heat flux was imposed

ABSTRACT Four kinds of microchannels with round grooves and ribs were designed: round grooves (round), round grooves and single–sided ribs (round–single), round grooves and odd-symmetric ribs (round–odd), and round grooves and doubly symmetric ribs (round–double). The effects of rib arrangement on the heat transfer performance of microchannels with round grooves and ribs were numerically investigated

ABSTRACT Heat transfer over a heated plate positioned normal to the horizontal circular impinging jet is investigated experimentally. The area average and local heat transfer characteristics over a large plate impinged by jet of air are investigated for Reynolds numbers ranging from 10,000 to 45,000, with jet-to-plate distances of 3–20 d for a maximum range of 0 ≤ r/d ≤ 44. The experiment is carried

ABSTRACT The present work focuses on the experimental and large-eddy simulation (LES) investigation of fluid flow and heat transfer due to the impingement of an unconfined turbulent slot jet on a smooth flat plate. Three LES sub-grid scale models are validated with the experimental observations for first time in terms effect of slot widths. A detailed parametric study is conducted considering nozzle

ABSTRACT In this paper, two special-shaped separated heat pipes with different condensation section structures are designed. The working medium is water, and the filling rate is 65%. The evaporation section is placed in the hot water tank, and the condensation section is equipped with a cold water jacket. The effects of different structures of condensing section on the thermal performance of separated

ABSTRACT A novel regenerative heat exchanger was designed and fabricated for heat recovery of dryer flue gases with a high porosity matrix core that was made of alumina foams. The effects of matrix height, matrix linear speed, and flow rate on thermal effectiveness were investigated based on an L25 Taguchi model. Results show that the matrix height and flow rate are inversely related and the matrix

ABSTRACT We report one of the first experimental investigation on simultaneous mapping of whole field temperature and velocity data to demonstrate the potential of thermographic PIV (or LIP/PIV) in the context of natural convection for a back-wall heated open square cavity. As part of the validation exercise, LIP/PIV-based results are compared with corresponding numerically simulated and interferometry-based

ABSTRACT In this study, the flow and heat transfer characteristics of microencapsulated phase change material (MPCM) slurry were experimentally investigated using a newly designed helical coil heat transfer device. The conventional helical coil has been structurally modified with passive enhancement features aiming to further promote fluid mixing. Specifically, 360° plastic tubing with or without wire

ABSTRACT The PCHE has been recognized as a promising heat exchanger for hypersonic precooled aero-engines due to its superior thermal performance, high compactness and robustness. The present work focuses on the experimental thermal-hydraulic performance study of a novel zigzag microchannel PCHE. The results indicate that the pressure loss caused by friction is the main source. The Fanning correlation

ABSTRACT The spray cooling is investigated for a high-temperature steel plate using varying temperature coolant for different nozzle-plate orientations. Before experimentation with very-high mass-flux spray, droplet-train impact assessment indicates liquid film breakup intensification down the inclined plane. The heat transfer analysis suggests a significant cooling performance change with an inclination

ABSTRACT An experimental setup has been developed to measure the thermal state of a conical antenna cooled by means of porous media saturated with water-based copper nanofluid. Thermal conductivity of the used porous materials varies between 4 and 41.2 times that of the water which constitutes the base fluid of the nanofluid whose volume fraction ranges from 0% (pure water) to 5%. The antenna is placed

ABSTRACT The initial transient behavior of condensation of water vapor from humid air plays vital roles in a large variety of engineering applications. Although such influences on the steady-state attributes of dropwise and filmwise condensations have been widely investigated in the literature, description of their initial transient behaviors is rather limited. Herein we have characterized the initial

ABSTRACT A novel turbulated cutback structure is designed for trailing-edge cooling, which has smooth-transition protrusions on the cutback surface. Experimental investigations are carried out on the effects of the protrusion configuration and the blowing ratio M on adiabatic cooling effectiveness and convective heat transfer coefficient of the cutback surface using transient thermochromic liquid crystal

ABSTRACT This manuscript presents an experimental study on heat transfer and pressure drop of two aluminum lattice-frame materials obtained via additive manufacturing, varying the air flow rate and the electrical power. A round shape and an airfoil shape samples were compared. The second one was proposed to reduce pressure drops. It was measured that pressure drop decreased on average by 5% maintaining

ABSTRACT The paper presents a gas-water heat exchanger based on the technology of a microheat pipe. The heat exchanger parameters, such as inlet and outlet temperature of flue gas, wind speed and inlet and outlet temperature of the water, were measured in practice. The analysis data showed that the temperature difference between the flue gas and the flue gas before and after heat exchange increased

ABSTRACT An experimental investigation is conducted to study the two-phase heat transfer behavior of a shear-thinning Non-Newtonian (NN) fluid, i.e., “Massecuite,” at atmospheric pressure over bi-directional microstructured surfaces for the heat flux range from 70 to 200 kW/m2. Two-phase heat transfer characteristics of a Newtonian Fluid, that is, distilled water, is also studied for the sake of comparison

ABSTRACT Bauxite and silica particles are candidate materials for solar thermal energy storage at high temperatures. The temperature-dependent emittance of packed beds with bauxite and silica particles was measured using a newly upgraded emissometer at wavelengths 2 μm ≤ λ ≤ 16 μm and temperatures up to ~730 K. The room-temperature emittance was obtained from the measured directional-hemispherical

ABSTRACT Three-dimensional reconstructions of thermal field in a differentially heated cylindrical cavity with dilute concentrations of nanofluids as the working medium have been reported. Experiments have been conducted in a specially designed tomography cell filled with dilute concentrations of Al2O3 nanofluids with ethylene glycol dimethacrylate (EGD) as the basefluid. The two horizontal walls of

ABSTRACT The influence of surface structures on the wettability and evaporation of a heated water drop is investigated both in the presence of a graphene layer and without a graphene coating. Different topology of surface roughness changes the structuring of water near nano-micro textures. The structured wall surface changes both the wettability and the evaporation rate. Molecular dynamics modeling

ABSTRACT In this study, a new design has been developed to increase the thermal performance of a plate heat exchanger. In the developed design, springs are placed on the heat exchanger plates at an angle of 45°. In this study, which aims to improve heat transfer by increasing turbulence, nanoparticles were also used to increase the heat transfer coefficient of the heat transfer fluid. The nanoparticles