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Showing 1 to 16 of 16 for “"Heat exchanger performance"”.
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A Study of Two-Phase Refrigerant Behavior in Flattened Tubes
… the effect of flattening a tube on total heat exchanger performance. Benefits of flattening the tube include a substantial decrease in refrigerant mass, and a slightly decrease in overall tube length.
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Heat Transfer Enhancement Using Tip and Junction Vortices
This research is important in compact heat exchanger design. Enhancing heat transfer can lead to smaller, more efficient heat exchangers in a broad range of applications. A simplified heat exchanger performance evaluation method is considered to explore the heat transfer benefit and pressure-drop …
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Experimentally validated models of refrigerant distribution in microchannel heat exchangers used to evaluate charge reduction of various working fluids
… 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 R134a are used …
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A Comprehensive Numerical Investigation of Heat Transfer Dynamics in Supercritical Carbon Dioxide Cooling
… carbon dioxide (sCO<sub>2</sub>) is an ideal heat transfer medium in energy and industrial applications due to its exceptional thermophysical properties near its critical point. However, experimental studies and numerical modeling of sCO<sub>2</sub> face significant challenges, such as …
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Analysis of steam and hydronic compartment heating systems aboard U.S. Coast Guard 140 foot WTGB class cutters
The compartment heating system on the U.S. Coast Guard's Icebreaking Tug (WTGB) class cutter was studied to determine heat transfer performance characteristics of existing heat exchangers when used with circulating hot water vice steam. Characterizations such as Reynolds number vs. Colburn j factor …
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Design and manufacturing of novel hybrid metal-polymer heat exchangers
Nearly 60% of waste heat from industrial processes in the U.S. lies in low-temperature regime (<200°C). Current conventional metal heat exchangers for waste heat recovery (WHR) of low-grade heat are too expensive and subject to corrosion from condensates below <150°C. Polymers, although an …
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The effect of external corrosion on the performance of multichannel multilouvered fin aluminum heat exchangers
… the effect of external corrosion of the aluminum heat exchangers on their performance, the air-side pressure drop and the UA of two identical aluminum multichannel multilouvered heat exchangers are evaluated periodically during ten days of salt spray test refers to ASTM G85 Annex 3 the acidified …
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Design and performance characterization of high power density air-cooled compact condenser heat exchangers
… of ultra-compact air-cooled condenser heat exchangers with exceptional power density performance in excess of 100 W/cm3. This exceptional heat exchanger performance is attributed to the implementation of high-speed compressible air flow in circular microchannels and two-phase …
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Characterization of Two -Phase Flow in Microchannels
… Three parameters are necessary to analyze a heat exchanger performance: heat transfer, pressure drop, and void fraction. The purpose of this investigation is the experimental investigation of void fraction and frictional pressure drop in microchannels. A flow visualization analysis is another …
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Metal foams as novel materials for air-cooling heat exchangers
… they are being considered for a range of heat transfer applications. In this experimental study, open-cell aluminum metal foam is considered as a replacement for conventional louvered fins in brazed-aluminum heat exchangers. Closed-loop wind tunnel experiments are conducted to measure the …
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Manufacturing and analysis of a LIGA heat exchanger for the surface of a tube: a cooling simulation of the leading edge region of a turbine blade
Fabricating nickel micro heat exchangers directly on planar or non-planar metal surfaces has been demonstrated using the LIGA micromachining process. These heat exchangers can effectively control the temperature of surfaces in high heat flux applications. Of particular interest is the temperature …
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The Method of Constructal Design in Heat Exchangers
… applying the Constructal design methodology of heat exchangers to the thermal and flow performance of such architectures. Based on the method of Constructal design, the system performance can be enhanced by providing its architecture or configuration more freedom to morph. Throughout this …
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Vortex-enhanced heat transfer by a new delta-winglet array
Liquid-to-air and phase-change heat exchanger performance is crucial to meet efficiency standards with low cost and environmental impact in numerous end-use energy applications. Research on performance improvement of heat exchangers often focuses on the air side because transport coefficients are …
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Experimental and modeling study of lubricant effect on refrigerant distribution in microchannel evaporators
Microchannel heat exchanger has been used in industry for decades. But the problem of refrigerant maldistribution can significantly deteriorate the performance of heat exchanger (especially evaporator) and system. In real air conditioning systems especially automobile air conditioning systems where …
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Flow distribution in brazed plate heat exchangers
Brazed plate heat exchangers (BPHEs) have been widely used in the heating, ventilating, air conditioning, and refrigeration (HVAC&R) industry for their compactness and high heat transfer coefficient. However, they suffer from the flow maldistribution among parallel plate channels. Especially when …
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Liquid-infused slippery surfaces for air-conditioning and refrigeration applications
… water retention and enhance thermal-hydraulic performance for air-conditioning and refrigeration (AC&R) applications. The results demonstrate that the LISs has a sliding angle smaller than 5˚ and reduces the water retention ratio after defrosting by more than 75% compared to the baseline …