Convective heat transfer on flat and concave surfaces subjected to an impinging jet form lobed nozzle

2019 ◽  
Vol 63 (1) ◽  
pp. 116-127 ◽  
Author(s):  
YuanWei Lyu ◽  
JingZhou Zhang ◽  
BoYan Wang ◽  
XiaoMing Tan
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Impinging Jet ◽  
Lobed Nozzle

Numerical and Experimental Study of Flow and Convective Heat Transfer on a Rotor of a Discoidal Machine with Eccentric Impinging Jet

2019 ◽  
pp. 1-29
Author(s):  
Chadia Haidar ◽  
Rachid Boutarfa ◽  
Mohamed Sennoune ◽  
Souad Harmand
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Steady State ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Air Flow ◽  
Impinging Jet ◽  
Rotating Disk ◽  
Reynolds Numbers ◽  
Air Jet

This work focuses on the numerical and experimental study of convective heat transfer in a rotor of a discoidal the machine with an eccentric impinging jet. Convective heat transfers are determined experimentally in steady state on the surface of a single rotating disk. The experimental technique is based on the use of infrared thermography to access surface temperature measurement, and on the numerical resolution of the energy equation in steady-state, to evaluate local convective coefficients. The results from the numerical simulation are compared with heat transfer experiments for rotational Reynolds numbers between 2.38×105 and 5.44×105 and for the jet's Reynolds numbers ranging from 16.5×103 to 49.6 ×103. A good agreement between the two approaches was obtained in the case of a single rotating disk, which confirms us in the choice of our numerical model. On the other hand, a numerical study of the flow and convective heat transfer in the case of an unconfined rotor-stator system with an eccentric air jet impinging and for a dimensionless spacing G=0.02, was carried out. The results obtained revealed the presence of different heat transfer zones dominated either by rotation only, by the air flow only or by the dynamics of the rotation flow superimposed on that of the air flow. Critical radii on the rotor surface have been identified

Effect of Reynolds Number, Hole Patterns and Hole Inclination on Cooling Performance of an Impinging Jet Array: Part I — Convective Heat Transfer Results and Optimization

2016 ◽  
Author(s):  
Weihong Li ◽  
Xueying Li ◽  
Jing Ren ◽  
Hongde Jiang ◽  
Li Yang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Impinging Jet ◽  
Target Plate ◽  
New Correlation

This study comprehensively illustrates the effect of Reynolds number, hole spacing, jet-to-target distance and hole inclination on the convective heat transfer performance of an impinging jet array. Highly resolved heat transfer coefficient distributions on the target plate are obtained utilizing transient liquid crystal over a range of Reynolds numbers varying between 5,000 and 25,000. Effect of streamwise and spanwise jet-to-jet spacing (X/D, Y/D: 4–8) and jet-to-target plate distance (Z/D: 0.75–3) are employed composing a test matrix of 36 different geometries. Additionally, the effect of hole inclination (θ: 0°–40°) on the heat transfer coefficient is investigated. Optical hole spacing arrangements and impingement distance are pointed out to maximize the area-averaged Nusselt number and minimize the amount of cooling air. Also included is a new correlation, based on that of Florschuetz et al., to predict row-averaged Nusselt number. The new correlation is capable to cover low Z/D∼0.75 and presents better prediction of row-averaged Nusselt number, which proves to be an effective impingement design tool.

Combination of PIV and PLIF methods to study convective heat transfer in an impinging jet

2017 ◽  
Vol 80 ◽  
pp. 139-146 ◽  
Author(s):  
Alexandr S. Nebuchinov ◽  
Yuriy A. Lozhkin ◽  
Artur V. Bilsky ◽  
Dmitriy M. Markovich
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Impinging Jet

Effect of Reynolds Number, Hole Patterns, and Hole Inclination on Cooling Performance of an Impinging Jet Array—Part I: Convective Heat Transfer Results and Optimization

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Weihong Li ◽  
Xueying Li ◽  
Li Yang ◽  
Jing Ren ◽  
Hongde Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Impinging Jet ◽  
New Correlation ◽  
Jet Array

This study comprehensively illustrates the effect of Reynolds number, hole spacing, jet-to-target distance, and hole inclination on the convective heat transfer performance of an impinging jet array. Spatially resolved target surface heat transfer coefficient distributions are measured using transient liquid crystal (TLC) measurement techniques, over a range of Reynolds numbers from 5000 to 25,000. Considered are effects of streamwise and spanwise jet-to-jet spacing (X/D, Y/D: 4–8) and jet-to-target plate distance (Z/D: 0.75–3). Overall, a test matrix of 36 different configurations is employed. In addition, the effect of hole inclination (θ: 0–40 deg) on the heat transfer coefficient is investigated. Optimal hole spacing arrangements and impingement distance are pointed out to maximize the area-averaged Nusselt number and minimize the amount of cooling air. Also included is a new correlation, based on that of Florschuetz et al., to predict row-averaged Nusselt number. The new correlation is capable to cover low Z/D ∼ 0.75 and presents better prediction of row-averaged Nusselt number, which proves to be an effective impingement design tool.

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