Numerical and Experimental Investigation of Flow and Heat Transfer in Heat Exchanger Channels with Different Dimples Geometries

The heat exchanger is widely applied to many axial piston machines, and its structure significantly affects the heat transfer performance. Flow characteristic and heat transfer performance in heat exchanger channels with different dimples geometries are numerically and experimentally analyzed in thi...

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Main Authors: Pingting Ying, You He, Hesheng Tang, Yan Ren
Format: Article
Language:English
Published: MDPI AG 2021-03-01
Series:Machines
Subjects:
Online Access:https://www.mdpi.com/2075-1702/9/4/72
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author Pingting Ying
You He
Hesheng Tang
Yan Ren
author_facet Pingting Ying
You He
Hesheng Tang
Yan Ren
author_sort Pingting Ying
collection DOAJ
description The heat exchanger is widely applied to many axial piston machines, and its structure significantly affects the heat transfer performance. Flow characteristic and heat transfer performance in heat exchanger channels with different dimples geometries are numerically and experimentally analyzed in this research work. The objective is to present details of flow field structure and heat transfer mechanisms for the dimpled channel. The realizable <i>k</i>-<i>ε</i> turbulence model was employed in the numerical simulations with the <i>R</i>e range from 3500 to 20,000. The temperature contour, local streamlines, friction factor, and <i>Nu</i> were presented to illustrate the heat transfer enhancement mechanisms. From this investigation, it is found that dimples cause downward flow, improve the flow mixing and reattachment, interrupt the boundary layer and form periodic impingement flows and then greatly improve the heat transfer. The heat transfer coefficient of hemispherical dimple channels with the three kinds of dimple radius–depth ratios is the highest, and it is about 27.2% higher than that of the traditional rhombus dimple channel. Comparing to the rhombus dimpled channel, the lower flow friction performance of the hemispherical dimple channel depends on the lower dimple radius–depth ratio. The hemispherical dimpled channel present better overall thermal performance due to the strength and extent of the recirculation flow reduction.
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spelling doaj.art-d820e42ecb5a4ba4b028cc1ecb7518fd2023-11-21T12:09:57ZengMDPI AGMachines2075-17022021-03-01947210.3390/machines9040072Numerical and Experimental Investigation of Flow and Heat Transfer in Heat Exchanger Channels with Different Dimples GeometriesPingting Ying0You He1Hesheng Tang2Yan Ren3School of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325035, ChinaThe State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, ChinaSchool of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325035, ChinaSchool of Mechanical and Electrical Engineering, Wenzhou University, Wenzhou 325035, ChinaThe heat exchanger is widely applied to many axial piston machines, and its structure significantly affects the heat transfer performance. Flow characteristic and heat transfer performance in heat exchanger channels with different dimples geometries are numerically and experimentally analyzed in this research work. The objective is to present details of flow field structure and heat transfer mechanisms for the dimpled channel. The realizable <i>k</i>-<i>ε</i> turbulence model was employed in the numerical simulations with the <i>R</i>e range from 3500 to 20,000. The temperature contour, local streamlines, friction factor, and <i>Nu</i> were presented to illustrate the heat transfer enhancement mechanisms. From this investigation, it is found that dimples cause downward flow, improve the flow mixing and reattachment, interrupt the boundary layer and form periodic impingement flows and then greatly improve the heat transfer. The heat transfer coefficient of hemispherical dimple channels with the three kinds of dimple radius–depth ratios is the highest, and it is about 27.2% higher than that of the traditional rhombus dimple channel. Comparing to the rhombus dimpled channel, the lower flow friction performance of the hemispherical dimple channel depends on the lower dimple radius–depth ratio. The hemispherical dimpled channel present better overall thermal performance due to the strength and extent of the recirculation flow reduction.https://www.mdpi.com/2075-1702/9/4/72heat exchangerdimple shapeheat transfer enhancementflow characteristicnumerical investigation
spellingShingle Pingting Ying
You He
Hesheng Tang
Yan Ren
Numerical and Experimental Investigation of Flow and Heat Transfer in Heat Exchanger Channels with Different Dimples Geometries
Machines
heat exchanger
dimple shape
heat transfer enhancement
flow characteristic
numerical investigation
title Numerical and Experimental Investigation of Flow and Heat Transfer in Heat Exchanger Channels with Different Dimples Geometries
title_full Numerical and Experimental Investigation of Flow and Heat Transfer in Heat Exchanger Channels with Different Dimples Geometries
title_fullStr Numerical and Experimental Investigation of Flow and Heat Transfer in Heat Exchanger Channels with Different Dimples Geometries
title_full_unstemmed Numerical and Experimental Investigation of Flow and Heat Transfer in Heat Exchanger Channels with Different Dimples Geometries
title_short Numerical and Experimental Investigation of Flow and Heat Transfer in Heat Exchanger Channels with Different Dimples Geometries
title_sort numerical and experimental investigation of flow and heat transfer in heat exchanger channels with different dimples geometries
topic heat exchanger
dimple shape
heat transfer enhancement
flow characteristic
numerical investigation
url https://www.mdpi.com/2075-1702/9/4/72
work_keys_str_mv AT pingtingying numericalandexperimentalinvestigationofflowandheattransferinheatexchangerchannelswithdifferentdimplesgeometries
AT youhe numericalandexperimentalinvestigationofflowandheattransferinheatexchangerchannelswithdifferentdimplesgeometries
AT heshengtang numericalandexperimentalinvestigationofflowandheattransferinheatexchangerchannelswithdifferentdimplesgeometries
AT yanren numericalandexperimentalinvestigationofflowandheattransferinheatexchangerchannelswithdifferentdimplesgeometries