IRis

Title

Experimental Convection heat transfer and flow discharge coefficients for multiple confined jet impingement normal to a surface at close distances

Author(s)

Nathaniel Risler Rosso, Northeastern University

Advisor(s)

Mohammad E. Taslim

Date of Award

2011

Date Accepted

12-2011

Degree Grantor

Northeastern University

Degree Level

M.S.

Degree Name

Master of Science

Department or Academic Unit

College of Engineering, Department of Mechanical and Industrial Engineering

Keywords

mechanical engineering, array, axisymmetric, confined, cooling, impingement, Nusselt

Disciplines

Mechanical Engineering

Abstract

Nusselt numbers and discharge coefficients were measured for a square array of confined, in-line, submerged, cylindrical jets impinging onto a normal target surface at distances ranging from greater than to less than one jet diameter. Jet-to-jet spacing was varied from two to four jet diameters. A survey of available literature revealed a little to no information on heat transfer and discharge coefficients at impingement distances of less than one jet diameter. Experiments were conducted at Reynolds numbers ranging from 8900 to 57000. Discharge coefficients were measured for impingement distances ranging from 0.3 to infinity. Nusselt numbers were obtained for impingement distances ranging from 0.3 to 2.0 jet diameters.

Discharge coefficient data showed that altering jet spacing at impingement distances of one jet diameter or greater had little effect on discharge coefficient (C_d). Increases in C_d as jet spacing was raised tended to amplify as impingement distance was decreased below one jet diameter. Decreases in C_d grew with decreasing impingement distance. Heat transfer data showed highest area-weighted Nusselt numbers (Nu_jet) at an impingement distance of one jet diameter. Increasing jet spacing resulted in degradation of heat transfer, except beyond crossover points at certain Reynolds numbers. Inner jets in the array experienced more pronounced effects from changing jet spacing and impingement distance than outer jets. While jet impingement is employed in a wide array of industrial applications, the focus of this study was impingement cooling in gas turbine engines.

Document Type

Master's Thesis

Rights Information

copyright 2011

Rights Holder

Nathaniel Risler Rosso

Permanent URL

http://hdl.handle.net/2047/d20002113

Recommended Citation

Rosso, Nathaniel Risler, "Experimental Convection heat transfer and flow discharge coefficients for multiple confined jet impingement normal to a surface at close distances" (2011). Mechanical Engineering Master's Theses. Paper 48. http://hdl.handle.net/2047/d20002113