Numerical study of the air inlet angle influence on the air–side performance of plate-fin heat exchangers

2015 ◽  
Vol 89 ◽  
pp. 356-364 ◽  
Author(s):  
Zhiying Liu ◽  
Hui Li ◽  
Lin Shi ◽  
Yangjun Zhang
Keyword(s):  
Heat Exchangers ◽  
Numerical Study ◽  
Air Inlet ◽  
Inlet Angle

Bejan’s Constructal Theory Analysis of Gas-Liquid Cooled Finned Modules

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Giulio Lorenzini ◽  
Simone Moretti
Keyword(s):  
Thermal Behavior ◽  
Heat Exchangers ◽  
High Performance ◽  
Numerical Study ◽  
Constructal Theory ◽  
Electronic Components ◽  
Theory Analysis ◽  
Pressure Losses ◽  
Different Types ◽  
Overall Performance

High performance heat exchangers represent nowadays the key of success to go on with the trend of miniaturizing electronic components as requested by the industry. This numerical study, based on Bejan’s Constructal theory, analyzes the thermal behavior of heat removing fin modules, comparing their performances when operating with different types of fluids. In particular, the simulations involve air and water (as representative of gases and liquids), to understand the actual benefits of employing a less heat conductive fluid involving smaller pressure losses or vice versa. The analysis parameters typical of a Constructal description (such as conductance or Overall Performance Coefficient) show that significantly improved performances may be achieved when using water, even if an unavoidable increase in pressure losses affects the liquid-refrigerated case. Considering the overall performance: if the parameter called Relevance tends to 0, air prevails; if it tends to 1, water prevails; if its value is about 0.5, water prevails in most of the case studies.

scholarly journals Numerical Simulation for Flow of Rolling Piston Type of Rotary Compressor

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2526
Author(s):  
Li-Chieh Hsu ◽  
Guo-Wei Wong ◽  
Po-Jui Lu ◽  
Fu-Shun Hsu ◽  
Ying-Chien Chen
Keyword(s):  
Numerical Study ◽  
Input Power ◽  
Rotary Compressor ◽  
Additional Resistance ◽  
Potential Factors ◽  
Reed Valve ◽  
Rolling Piston ◽  
Inlet Angle ◽  
Work Done ◽  
Design Margin

In this numerical study, the temperature, pressure and flow structure inside the rotary compressor are obtained to analyze the work consumption and efficiency. The geometry of the compressor such as volume, inlet angle, and mass of reed valve are varied to look for optimal performance and design margin as the suggestions for manufacturing. The work done on refrigerant increases proportionally with the volume of the compressor. However, there is an optimal volume for efficiency. The design margin for inlet angle is determined. The best efficiency exists in a specific inlet angle. Larger mass of reed valve leads to the increase of input power due to the additional resistance from greater inertia, which causes a decrease of efficiency. The flow visualization by simulation diagnoses the potential factors, which may cause noise problem.

scholarly journals Numerical Study of Flow Maldistribution in Multi-Plate Heat Exchangers Based on Robust 2D Model

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3121 ◽  
Author(s):  
Arkadiusz Brenk ◽  
Pawel Pluszka ◽  
Ziemowit Malecha
Keyword(s):  
Heat Exchangers ◽  
Numerical Study ◽  
High Heat ◽  
Pressure Balance ◽  
Plate Heat ◽  
Pressure Losses ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Wide Range ◽  
Flow Maldistribution

Plate heat exchangers (PHE) are characterized by high heat transfer efficiency and compactness. An exploitation problem of the PHE is related to flow maldistribution, which can make part of the PHE idle, resulting in overheating and damage. Making geometrical modifications to the PHE can help reduce flow maldistribution. Modifications should be kept to a minimum, so as not to complicate the production process. There is a large number of possible geometrical modifications, which simply considers additional obstacles or stream dividers. To test all of them would be impractical and would also take a prohibitively long amount of time to obtain experimental measurements. A typical PHE is characterized by a complex system of channels. Making numerical calculations of its 3D model can be prohibitively time and resource-consuming. The present work introduces a physically consistent methodology of the transformation of a real 3D geometry to its 2D representation. Its main novelty is to assure the same pressure drop balance remains between the 3D and 2D geometries. This is achieved by a preservation of the same cumulative pressure losses in both geometries. The proposed innovative approach levels the pressure balance difference by adding properly designed local geometrical modifications. The developed methodology allowed a wide range of parameter space and various geometrical modifications to be investigated, and revealed geometrical optimizations leading to the improved performance of the PHE. To minimize the influence of other factors, an incompressible and single-phase flow was studied.

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