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Showing 1 to 14 of 14 for “"microchannel heat exchangers"”.
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Pressure drop in headers of microchannel heat exchangers
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-05-01
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The void fraction in headers of microchannel heat exchangers
In HVAC&R systems, microchannel heat exchangers (MCHEs) are commonly used with the advantages of compactness, the potential for reduction of charge, and improvement of heat transfer performance compared to other traditional heat exchangers. The void fraction in the headers affects the thermal …
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Numerical optimisation and theoretical analysis of complex microchannel heat exchangers
… of the geometries in forced convective heat transfer and steady state laminar incompressible fluid flow. Microchannel heat sinks used were numerically modelled from highly conductive (aluminium) solid material substrate. ANSYS FLUENT Response Surface Optimisation Tool (RSO) was used to …
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Refrigerant flow distribution in vertical headers of reversible microchannel heat exchangers
An outdoor reversible microchannel heat exchanger, typically having vertical headers and more than two passes, may be used in either air-conditioning or heat pump mode in a reversible system. In heat pump mode, it functions as an evaporator and refrigerant maldistribution among parallel …
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An Analytical and Empirical Study of Frost Accumulation Effects on Louvered -Fin, Microchannel Heat Exchangers
… time-varying performance of folded-louvered-fin, microchannel heat exchangers. The model utilizes the correlations developed from the experimental data and incorporates a sub-model for frost properties. The model successfully predicts the heat transfer performance of the heat exchangers studied, …
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Study of the effects of external corrosion on the thermal-hydraulic performance of brazed aluminum microchannel heat exchangers
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2026-12-01
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Experimentally validated models of refrigerant distribution in microchannel heat exchangers used to evaluate charge reduction of various working fluids
… developed to obtain accurate prediction of microchannel heat exchanger performance and charge. Effects of using various correlations are presented and discussed with focus on microchannel condensers and evaporators. Experiments with different refrigerants including R290, R717, R1234yf, and …
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Drawn Polymer Fiber Recuperative Heat Exchangers
Polymer microchannel heat exchangers for use in cryocooler applications have been developed. These heat exchangers are manufactured using a thermal drawing process where a bulk polymer preform is heated and stretched. The process results in channels with a characteristic dimension of 50-100 µm and …
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Coupling complex microchannel heat exchanger CFD with plug flow and Poiseuille flow models
Microchannel heat exchanger simulation provides a means to obtain design predictions at low cost and quick turnaround. Using computational fluid dynamics to solve the conjugate heat transfer problem, key output metrics such as overall pressure drop, heat exchanger effectiveness, and heat exchanger …
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Two-Phase Pressure Drop and Flow Regime of Refrigerants and Refrigerant -Oil Mixtures in Small Channels
As microchannel heat exchangers have become more sophisticated in their design, more exact understanding of the flow inside them is necessary. A decrease in diameter enhances the heat transfer (which takes place at the inner walls of the tubes), but also increases the pressure drop (as the diameter …
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Impact of heat exchanger surface wettability on condensation, frosting, and defrosting performance under practical testing conditions
Condensation and frost accumulation on aluminum heat exchangers present major challenges for heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems. Both phenomena increase thermal resistance and airflow restriction, which diminish heat transfer, lower system capacity, and drive …
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Multiscale computational simulation of multidimensional chemically reacting flow over washcoated heterogeneous catalysts
… The simulation and evaluation of a novel ceramic microchannel heat exchanger; the adaptation of in situ adaptive tabulation for the acceleration of transient, heterogeneous chemistry in large CFD models; and the development of catalytic washcoat performance relations informed by 3D reconstructions …
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Two phase flow distribution in parallel flow heat exchangers -- experimentally verified model
… of refrigerant is a problem in parallel microchannel heat exchangers that lowers their potential effectiveness, especially when controlled by superheat. This paper describes modeling and numerical simulation of two phase mass flow distribution in a microchannel evaporator, on the basis of …
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Periodic reverse flow in microchannel evaporators
… a very commonly seen phenomenon in small scale heat removal applications, for instance, microchannel heat sinks for cooling of electronics. Due to the industry’s strict requirement for thermal stability, previous research on flow instabilities in microchannels has been largely focused on heat …