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Showing papers on "Heat transfer coefficient published in 2022"


Journal ArticleDOI
TL;DR: In this paper , the convection heat transfer in a countercurrent double-tube heat exchanger with various fins in a turbulent flow is investigated, and the results show that the water aluminum oxide nanofluid has a better convective heat transfer coefficient than water titanium dioxide and pure water.

55 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of parameters such as spacing, EG (expanded graphite) content, battery direction, coolant flow rate and pipe diameter on the cooling performance was analyzed.

53 citations


Journal ArticleDOI
TL;DR: In this article , a composite cooling system coupled with PCM (phase change material) and liquid cooling was designed, and the influence of parameters such as spacing, EG (expanded graphite) content, battery direction, coolant flow rate and pipe diameter on the cooling performance was analyzed.

46 citations


Journal ArticleDOI
TL;DR: In this paper , the effect of thermal resistance variation on the heat transfer performance near the pseudo-critical point was analyzed, where a novel type of PCHE with airfoil fins was proposed and tested.

40 citations


Journal ArticleDOI
TL;DR: In this paper , the effect of combining two different bifurcation level fractal fins was considered for PCM melting heat transfer in a phase change heat exchanger, and the results showed that the complete melting time of PCM in a combined fractal fin heat exchange was reduced by 68% compared with the traditional fractal tail heat exchange.
Abstract: The melting heat transfer characteristics of PCM were studied in different combined types of heat exchangers. The effect of combining two different bifurcation level fractal fins was considered for PCM melting heat transfer in a phase change heat exchanger. Based on fractal theory and enthalpy-porosity method, a PCM melting model of two-dimensional unsteady heat transfer was established in a combined fractal fin heat exchanger. The influences of some factors, such as combined types of fractal fins, bifurcation level, heat transfer area of the fins and the spacing of the fins, were discussed for the melting heat transfer process. The results show that the complete melting time of PCM in a combined fractal fin heat exchanger is reduced by 68% compared with the traditional fractal fin heat exchanger. The melting time shows decreasing first and then gradually stabilizing as the bifurcation level number and heat transfer area of the combined fractal fins increase. The melting rate of PCM is the fastest in the Case 4 heat exchanger, and the complete melting time of PCM is the shortest in the Case 3 heat exchanger. Fin spacing and heat transfer area have a significant impact on the complete melting time. On this basis, the thermal performance coefficients between the fins zone and PCM zone are defined. The complete melting time of PCM is found to be exponentially negatively correlated with the thermal performance coefficient by curve fitting. The temperature distribution uniformity coefficient is proposed to evaluate the temperature distribution uniformity during the melting process of PCM. It is found that the temperature distribution uniformity of Case 2 has the best at the end of melting. The above results provide a theoretical basis for structural design of the heat exchanger with combined fractal fins to enhance PCM melting heat transfer.

32 citations


Journal ArticleDOI
TL;DR: In this article , multilayer perceptron type artificial neural network (MLP-ANN) was employed to map and forecast the thermal performance of MWCNT nanofluids on the tube side and water on the shell side.

31 citations


Journal ArticleDOI
TL;DR: In this paper , a comprehensive analysis consisting of computational fluid dynamics (CFD) and machine learning algorithms (MLAs) was conducted to study the effect of geometrical and operational parameters on nanofluid heat transfer in a microchannel heat sink (MCHS) with double synthetic jets (SJs).

31 citations


Journal ArticleDOI
TL;DR: In this paper , the thermal effects of using Al2O3-syltherm oil nanofluid with different concentrations and new flange-shaped turbulators are investigated.

31 citations


Journal ArticleDOI
TL;DR: In this article, an experimental and numerical investigation on the thermofluidic performance of Al2O3-water nanofluids through oblique fin heat sink microchannel (OFHS MC) was presented.

26 citations


Journal ArticleDOI
TL;DR: In this article, the effect of the copper metal foam proportion on heat transfer enhancement in the melting process of phase change materials was analyzed using visualisation heat storage experimental equipment, and the integrated heat transfer coefficient was obtained.

26 citations


Journal ArticleDOI
TL;DR: In this article , the authors proposed a 3D heat transfer model that considers contact heat transfer and thermal cracking in continuous-discontinuous media, and the model is combined with the 3D Finite Discrete Element (FDEM) for coupled thermo-mechanical calculation, which includes the temperature distribution of the system, the thermal stress caused by the temperature, and finally, the newly generated broken joint element is updated for heat transfer calculation at the next time.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a 3D heat transfer model that considers contact heat transfer and thermal cracking in continuous-discontinuous media, and the model is combined with the 3D Finite Discrete Element (FDEM) for coupled thermo-mechanical calculation, which includes the temperature distribution of the system, the thermal stress caused by the temperature, and finally, the newly generated broken joint element is updated for heat transfer calculation at the next time.

Journal ArticleDOI
TL;DR: In this paper , an experimental and numerical investigation on the thermofluidic performance of Al2O3-water nanofluids through oblique fin heat sink microchannel (OFHS MC) in the Reynolds number range 100-300.


Journal ArticleDOI
TL;DR: In this article , a cubic pack of nine cylindrical type lithium-ion batteries with three separate ducts to convey alumina (Al 2 O 3 )/water nanofluids (NFs), and all the assembly of battery cells and ducts are then dipped in phase-change material (PCM).

Journal ArticleDOI
15 Jan 2022-Energy
TL;DR: In this article, a novel concentric annular thermoelectric generator (CATEG) consisting of a concentric thermocouple and an annular heat exchanger is proposed.

Journal ArticleDOI
TL;DR: In this article , the authors used hybrid nanofluids and various turbulence-inducing elements to increase the convective heat transfer coefficient (HTC) of the flat plate solar collector.

Journal ArticleDOI
TL;DR: In this article , the saturated pool boiling heat transfer performance on the surface of T-shaped micro-fins was investigated with deionized water as working medium, which showed that the merging of bubbles on the outside of the channel surface could strengthen the vertical and horizontal replenishment of the liquid to dry spot in the channel, thereby delaying the occurrence of critical heat flux.

Journal ArticleDOI
TL;DR: In this paper, a double-slope solar still using a hybrid nanofluid (Al2O3-TiO2) at a concentration of 0.4% was evaluated.

Journal ArticleDOI
TL;DR: In this article , the authors performed an in-depth analysis of the preparation, stability, and thermophysical properties of GNP nanofluids, and their applications in heat exchangers, solar thermal collectors, and heat pipes.

Journal ArticleDOI
TL;DR: In this article, a punched delta winglet (PDW) was proposed and investigated numerically and experimentally in a turbulent flow, and the effect of delta winglets with different punching holes on heat transfer performance was studied.

Journal ArticleDOI
TL;DR: In this article , the authors investigated the heat transfer performance of multwalled carbon nanotube nanoparticles (MWCNT) dispersed in a binary mixture of water-EG (ethylene glycol) at a volumetric ratio of 50:50 in an automotive radiator.

Journal ArticleDOI
TL;DR: In this article, 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 was studied.

Journal ArticleDOI
TL;DR: In this article , a quasi-liquid surface with ultralow contact angle hysteresis down to 1° showed a heat-transfer coefficient up to 70 and 380% higher than those on conventional hydrophobic and hydrophilic surfaces, respectively.
Abstract: Sustainable high-performance steam condensation is critical to reducing the size, weight, and cost of water and energy systems. It is well-known that dropwise condensation can provide a significantly higher heat-transfer coefficient than filmwise condensation. Tremendous efforts have been spent to promote dropwise condensation by achieving a nonwetting state on superhydrophobic surfaces and a slippery state on liquid-infused surfaces, but these surfaces suffer from severe durability challenges. Here, we report sustainable high-performance dropwise condensation of steam on newly developed durable quasi-liquid surfaces, which are easily made by chemically bonding quasi-liquid polymer molecules on solid substrates. As a result, the solid/water interface is changed to a quasi-liquid/water interface with minimal adhesion and extraordinary durability. The quasi-liquid surface with ultralow contact angle hysteresis down to 1° showed a heat-transfer coefficient up to 70 and 380% higher than those on conventional hydrophobic and hydrophilic surfaces, respectively. Furthermore, we demonstrated that the quasi-liquid coating exhibited a sustainable heat-transfer coefficient of 71 kW/(m2 K) at a heat flux of 420 kW/m2 under a prolonged period of 39 h in continuous steam condensation. Such a quasi-liquid surface has the potential to sustain high-performance dropwise condensation of steam and address the long-standing durability challenge in the field.

Journal ArticleDOI
TL;DR: In this article, the hydrodynamics and thermochemical characteristics of the sorption enhanced steam methane reforming process in a fluidized bed reactor are studied with a multiphase particle-in-cell model.

Journal ArticleDOI
TL;DR: In this article , a new SiO2-ethylene-glycol/deionized water nanofluids with excellent static storage and dynamic stability was prepared, and the experimental correlations were fitted.

Journal ArticleDOI
TL;DR: In this paper , the effects of regular triangular prism (TP) on thermal and hydraulic characteristics in a minichannel heat sink under inlet Reynolds number (Re) of 221-884 using numerical simulation were explored.

Journal ArticleDOI
TL;DR: In this article , a punched delta winglet (PDW) was proposed and investigated numerically and experimentally in a turbulent flow, and the effect of delta winglets with different punching holes on heat transfer performance was studied.

Journal ArticleDOI
TL;DR: In this article , a model of a multi-element thermoelectric refrigerator with radiative heat transfer law (RHT) and Newtonian heat transfer laws (NHT) is established based on finite time thermodynamics, and the sameness and difference of the characteristics with different form of heat transfer are compared by numerical examples.

Journal ArticleDOI
TL;DR: In this article , a new type of GNP-Fe3O4 hybrid nanoparticles is prepared, and the crystal structure test proves that it has high purity, contains a variety of hydrophilic functional groups, and has a strong binding force between elements.