Abstract
The objective of this study is to analyze experimentally and numerically the flow characteristics of a symmetric channel arisen from flow modeling of the blade cooling problem. The two ends of the flat channel are open and five evenly spaced air jets of equal strength at the upper wall configure a symmetrical flow around the mid-slot symmetry axis. The parameters that govern the flow characteristics of such a system are; the channel height, the jet spacing, and the jet velocity. In the analysis, the slot width is kept constant, but the channel height to slot width ratio ( ), and the slot spacing ratio ( ) vary in the range of 1-3 and 2-4 respectively. In addition, the flow Reynolds number (Re) is altered in a range between 1500 and 10500 for each channel geometry of nine combinations. In experiments, the pressure distributions by an electronic micro-manometer, and the velocity profiles by a hot-wire anemometry system are measured. In numerical approach, the realizable turbulence model with enhanced wall treatment is used for the turbulence computations. Comparisons with the experimental data obtained under isothermal conditions allow evaluation of the performance of the numerical model. The results show that the channel height is the dominant parameter that affects the flow characteristics and a correlation is proposed for determining the pressure drop coefficient of the injection section.
Highlights
Due to removing high heat flow rates, impinging jets have been employed for many engineering applications. Ebadian and Lin (2011) compared the different methods of high-heat flux heat removal including micro-channels, jet impingements, sprays, wettability effects, and piezo-electrically driven droplets
The effect of nozzle geometry on flow structure and heat transfer caused by multiple jet arrays are analyzed by Çalışkan et al, 2014 and by Attalla et al, 2017
( ) ( ) Fig. 1b, due to flow symmetry along xoy and yoz planes, one-fourth portion of the channel sized with the arrangement in length × height × width as 500 × (12.7, 25.4, 38.1) × 330 mm is considered as the computational domain
Summary
Due to removing high heat flow rates, impinging jets have been employed for many engineering applications. Ebadian and Lin (2011) compared the different methods of high-heat flux heat removal including micro-channels, jet impingements, sprays, wettability effects, and piezo-electrically driven droplets. Ebadian and Lin (2011) compared the different methods of high-heat flux heat removal including micro-channels, jet impingements, sprays, wettability effects, and piezo-electrically driven droplets. Due to removing high heat flow rates, impinging jets have been employed for many engineering applications. They found that jet impingement had higher heat flux removal than other cooling technologies. Thielen et al (2003) numerically studied the effect of nozzle arrangement on the heat transfer of multiple impinging axisymmetric jets. The effect of nozzle geometry on flow structure and heat transfer caused by multiple jet arrays are analyzed by Çalışkan et al, 2014 and by Attalla et al, 2017. The effect of nozzle geometry on flow structure and heat transfer caused by multiple jet arrays are analyzed by Çalışkan et al, 2014 and by Attalla et al, 2017. Gao (2003) conducted an experimental investigation into multiple jet impingement, and notified that due to cross flow effects, the stagnation
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