Jet Impingement Heat Transfer Enhancement on a rib-roughened Flat Plate

2016 ◽  
Author(s):  
A H. Alenezi ◽  
Joao Amaral Teixeira ◽  
Abdulmajid Addali A. ◽  
Abdelaziz Gamil A. A. ◽  
Hamad M. Alhajeri
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Transfer Enhancement ◽  
Jet Impingement ◽  
Transfer Enhancement ◽  
Impingement Heat Transfer ◽  
Rib Roughened

scholarly journals A Numerical and Experimental Investigation of Dimple Effects on Heat Transfer Enhancement with Impinging Jets

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 813 ◽  
Author(s):  
Parkpoom Sriromreun ◽  
Paranee Sriromreun
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Transfer Enhancement ◽  
Air Flow ◽  
Flow Characteristics ◽  
Jet Impingement ◽  
Impinging Jets ◽  
Transfer Enhancement ◽  
Test Plate ◽  
Hot Surface

This research was aimed at studying the numerical and experimental characteristics of the air flow impinging on a dimpled surface. Heat transfer enhancement between a hot surface and the air is supposed to be obtained from a dimple effect. In the experiment, 15 types of test plate were investigated at different distances between the jet and test plate (B), dimple diameter (d) and dimple distance (Er and Eθ). The testing fluid was air presented in an impinging jet flowing at Re = 1500 to 14,600. A comparison of the heat transfer coefficient was performed between the jet impingement on the dimpled surface and the flat plate. The velocity vector and the temperature contour showed the different air flow characteristics from different test plates. The highest thermal enhancement factor (TEF) was observed under the conditions of B = 2 d, d = 1 cm, Er= 2 d, Eθ = 1.5 d and Re = 1500. This TEF was obtained from the dimpled surface and was 5.5 times higher than that observed in the flat plate.

Heat Transfer Enhancement of Jet Impingement on a Flat Plate Attached by a Porous Medium with a Center Cavity

2010 ◽  
Vol 297-301 ◽  
pp. 427-432 ◽  
Author(s):  
Pey Shey Wu ◽  
Chia Yu Hsieh ◽  
Shen Ta Tsai
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Nusselt Number ◽  
Flat Plate ◽  
Porous Layer ◽  
Jet Impingement ◽  
Stagnation Zone ◽  
Transfer Enhancement ◽  
Maximum Enhancement ◽  
Impingement Heat Transfer

Jet impingement heat transfer on a target plate covered with a thick porous layer with or without a cylindrical center cavity is experimentally investigated using the transient liquid crystal technique. Based on the results of jet impingement on a bare flat plate, heat transfer enhancement due to the attachment of porous medium is assessed. The varying parameters in the experiments include the nozzle-to-plate distance, jet Reynolds number, jet-to-cavity diameter ratio, and the cavity depth. Results of Nusselt number distribution, stagnation-zone Nusselt number, and averaged Nusselt number over a region of 3 times the hole diameter are documented. Experimental results show that the attachment of the porous layer with a center cavity can either hamper, or effectively enhance the jet impingement heat transfer over a flat plate. The maximum enhancement occurs at jet Reynolds number of 12400 when the cavity is a through hole and the cavity has the same diameter as the jet. The stagnation-zone Nusselt number increases 58.3% and the averaged Nusselt number increases 77.5% at the maximum enhancement condition. On the other hand, the addition of the thick porous layer without a center cavity gave rise to severe adverse effect on jet impingement heat transfer.

scholarly journals Enhanced Full Coverage Impingement Heat Transfer With Obstacles in the Gap

1991 ◽  
Author(s):  
R. A. A. Abdul Hussain ◽  
G. E. Andrews
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Transfer Enhancement ◽  
Gas Turbine ◽  
Transfer Enhancement ◽  
Gas Turbine Combustor ◽  
Impingement Heat Transfer ◽  
Main Effect ◽  
Flow Situation ◽  
Large Flow

Impingement heat transfer with turbulence enhancing obstacles in the impingement gap were investigated and compared with the unobstructed flow situation. The objective was to significantly enhance flat plate impingement heat transfer for gas turbine combustor external wall cooling applications. Large flow blockages were used in the form of ribs and slotted ribs. The latter were found to have the best heat transfer enhancement of up to 23% at the trailing edge. The main effect of the blockage was to considerably reduce the influence of crossflow on the heat transfer by preventing the deflection of the impingement jets by the crossflow.

Investigations of Single Jet Impinging on Plates With Circular Dimples

2017 ◽  
Author(s):  
Zhiqiang Guo ◽  
Mei Zheng ◽  
Yinze Liu ◽  
Wei Dong
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Transfer Enhancement ◽  
Heat Transfer Performance ◽  
Enhancement Effect ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Impingement Heat Transfer ◽  
Single Jet ◽  
Different Depths

In this paper, experimental and numerical investigations are both conducted to study the effect of circular dimples on the heat transfer performance of jets impingement. The circular dimples, set as one kind of surface structures on flat plate, have the same diameter of 3 mm but with different depths: 1.2 mm, 0.9 mm and 0.6 mm. Furthermore, in order to understand the mechanism of impingement heat transfer with circular dimples deeply, three different jet locations are studied in this paper. For the experimental investigations, the infrared thermography is applied to gain the temperature distributions on the flat plate. A comparison is made between the numerical results and experimental data, which indicates that they are in good agreement. The numerical results show that the dimples on the plates have significant effects on the impingement heat transfer. The overall averaged and local heat transfer coefficient in a single jet impingement on the smooth and dimpled plates are obtained and compared, as well as the flow structure. The effect of the dimples on the heat transfer performance of the target plates is different for different locations of dimples. Velocity distributions and streamlines near the target plates are also shown to explain the heat transfer characteristics. From the investigations, for the dimpled plates with different depths, the deeper dimples have the better averaged heat transfer on the target plates. The dimpled surface enhances the heat transfer performance obviously with H/D of 1.5. However, with the distance between the impinging hole and the target plate increasing, the transition location of the impact zone and the wall jet zone advances and the enhancement effect decreases. Moreover, further downstream region on the dimpled plates shows lower heat transfer enhancement effect and the effect becomes approximately invisible after X/D is larger than 3. The fluid in the dimples with different depths has the same streamline. The heat transfer enhancement at the downstream of dimples is better than the upstream.

Pulsating Jet Impingement Heat Transfer Enhancement

2008 ◽  
Vol 26 (4) ◽  
pp. 433-442 ◽  
Author(s):  
W. Liewkongsataporn ◽  
T. Patterson ◽  
F. Ahrens
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Jet Impingement ◽  
Transfer Enhancement ◽  
Impingement Heat Transfer ◽  
Pulsating Jet
Sign in / Sign up

Export Citation Format

Share Document