An Experimental Investigation of Sheet Velocity and Jet Diameter Assumptions of Non-Newtonian Impinging Jets

2015 ◽  
Author(s):  
Patrick W. Collins ◽  
Jennifer Mallory
Keyword(s):  
Experimental Investigation ◽  
Impinging Jets

Experimental Investigation of Local Heat Transfer Distribution on Smooth and Roughened Surfaces Under an Array of Angled Impinging Jets

2004 ◽  
Vol 127 (3) ◽  
pp. 532-544 ◽  
Author(s):  
Lamyaa A. El-Gabry ◽  
Deborah A. Kaminski
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Local Heat Transfer ◽  
Target Surface ◽  
Reynolds Numbers ◽  
Local Heat ◽  
Impinging Jets ◽  
Temperature Data ◽  
Test Rig ◽  
Surface Temperature Data

Measurements of the local heat transfer distribution on smooth and roughened surfaces under an array of angled impinging jets are presented. The test rig is designed to simulate impingement with crossflow in one direction. Jet angle is varied between 30, 60, and 90deg as measured from the target surface, which is either smooth or randomly roughened. Liquid crystal video thermography is used to capture surface temperature data at five different jet Reynolds numbers ranging between 15,000 and 35,000. The effect of jet angle, Reynolds number, gap, and surface roughness on heat transfer and pressure loss is determined along with the various interactions among these parameters.

Experimental Investigation of Single-Phase Micro Jets Impingement Cooling for Electronic Applications

2003 ◽  
Author(s):  
Matteo Fabbri ◽  
Shanjuan Jiang ◽  
Vijay K. Dhir
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Free Surface ◽  
Single Phase ◽  
Impinging Jets ◽  
Heat Fluxes ◽  
Number Range ◽  
Impingement Cooling ◽  
Circular Arrays

Impinging jets for cooling of electronic equipment have been used by many researchers. Only few studies using arrays composed of a small number of jets are available in the literature. When very small jet diameters are used, the jet Reynolds number becomes quite small and no data are available for Reynolds number values below 500. In this work attention has been focused on circular arrays of free surface micro jets. Experiments were conducted by employing three jet pitches, 1, 2 and 3 mm and four jet diameters 50, 100, 150 and 250 μm and two different fluids, DI water and FC 40. The jet Reynolds number range was varied between 90 and 2000 while the Prandtl number varied from 6 to 84. Heat fluxes as high as 250 W/cm2 could be removed when water was utilized. Experimental data have been correlated within ±20%.

A Numerical and Experimental Investigation on Impinging Round Jets in Channel Partially Filled With Porous Media

2017 ◽  
Author(s):  
Bernardo Buonomo ◽  
Luca Cirillo ◽  
Oronzio Manca ◽  
Sergio Nardini
Keyword(s):  
Experimental Investigation ◽  
Porous Media ◽  
Metal Foam ◽  
Fluid Dynamic ◽  
Heated Surface ◽  
Impinging Jets ◽  
Solid Matrix ◽  
Uniform Heat Flux ◽  
Round Jets ◽  
Nusselt Numbers

In this paper a numerical and experimental investigation on impinging jets with metal foam is carried out. The channel is partially filled with porous media. The physical model and geometry has been made considering that the lower impinging surface is heated at uniform heat flux, qw, and the upper surface is adiabatic. The flow is 2D, unsteady, laminar, and incompressible. The distance between the upper confining surface and the lower heated surface is H (40 mm). Fully developed fluid dynamic and thermal flow is assumed at the outlet sections and the fluid is air. The porous material is considered as homogeneous and isotropic. All the thermophysical properties of the fluid and the solid matrix of the porous medium are assumed constant except for the variation in density with the temperature giving rise to the buoyancy forces. Metal foam of 10 PPI is considered. It was investigated many configuration taking into account the ratio s/H and Dj/H. The values of ratio s/H ranging from 0 to 1 while values of the ratio Dj/H raging from 0.3–1.2. Results in terms of wall temperature profiles, local and average Nusselt numbers are presented for different Reynolds values. For the considered parameters, it is obtained that Nusselt number has a weak dependence of Dj/H, in fact, for the ratio equal to 0.3, it is noted that Nu is higher than the ratio equal to 0.6.

Experimental Investigation of Overall Cooling Effectiveness on Combustion Chamber Liner With and Without Impingement Holes

2015 ◽  
Author(s):  
Felix Jesuraj ◽  
Raghavan Rajendran ◽  
Kumar Gottekre Narayanappa ◽  
Giridhara Babu Yepuri ◽  
Vivek Sasikumar ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Film Cooling ◽  
Impinging Jets ◽  
Parallel Plates ◽  
Transfer Coefficients ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Impingement Plate ◽  
Comparative Results

The gas turbine combustor liner which is subjected to high temperature requires efficient cooling. In earlier days concept of slot film cooling is utilized in the combustion liners and in modern combustors multiple row film cooling (effusion cooling) is mainly used. This study aims at the experimental investigation of overall film cooling effectiveness of an effusion plate with and without impingement holes at the backside. The experiments are done at different blowing ratios and the surface temperature measurements are taken using infrared thermography. The effusion and impingement holes are arranged in staggered manner on two parallel plates and each effusion hole is surrounded by four impingement holes. Effusion holes are drilled at an angle of 27° and the impingement plate is kept at a distance of 6D away from the effusion plate. The experiments are done on the effusion plate with and without impingement plate at the backside. The results show, increase in cooling effectiveness as the blowing ratio increases. The comparative results shows that at a particular blowing ratio the overall cooling effectiveness is higher for effusion plate with impingement holes at the backside due to the higher convective heat transfer coefficients produced by the impinging jets at the cold side of the effusion plate.

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