An Experimental Investigation Of The Flow Field And Heat Transfer From A Single Impinging Jet With Varying Confinement Conditions

Abstract

The high heat transfer capabilities of impinging jets have led to their widespread use in industrial applications, such as gas turbine cooling. In this gas turbine application, impingement holes are manufactured in the walls of superalloy metals, and thus, flow fields of impinging jets are influenced by this confinement. A large portion of existing literature on the subject of impingement does not consider this confinement, and focuses on a more fundamental application of impinging jets open flow fields. This study serves to investigate the resulting differences in the flow field and heat transfer for a semi-confined, axisymmetric, impinging jet originating from a sharp edge orifice. Several different jet diameters and confinement plate diameters are tested in order to achieve various levels of confinement. These results are compared to existing cases in literature which have significantly less confinement. The effects of entrainment and recirculation within the near stagnation flow field were investigated by measuring effectiveness, discharge coefficient, and heat transfer coefficient for the different testing conditions. Radial distributions of effectiveness are measured with high spatial resolution, and indicate there is an appreciable difference between differing confinement levels. The effects of variation in sink pressure is also studied by altering the pressure of the chamber, which houses the target surface, to several values between 0 - 1 psi. This was seen to have little effect on the resulting effectiveness distributions. The Reynolds number, based on jet diameter, in this study varied between 20,000 - 80,000, where the jet to target plate spacing varied between 2 and 6 jet diameters. The effectiveness distributions are Reynolds number independent, and only a function of jet to target surface spacing and the confinement condition. These conclusions are relatively consistent with cases found in literature, however, an appreciable difference is seen to exist which depends on the amount of confinement.

Publication Date

1-1-2016

Publication Title

52nd AIAA/SAE/ASEE Joint Propulsion Conference, 2016

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.2514/6.2016-5048

Socpus ID

85088071209 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85088071209

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