Document Type
Thesis
Date of Award
9-30-1984
Degree Name
Master of Science in Mechanical Engineering - (M.S.)
Department
Mechanical Engineering
First Advisor
P. Hrycak
Second Advisor
John Vincent Droughton
Third Advisor
P. Hrycak
Abstract
Experimental investigation was carried out on the flow characteristics of a circular, submerged, turbulent, array of axisymmetric air jets impinging normally on a smooth, flat, square, lucite plate. Jets issuing from an array of circular nozzles 0.25 and 0.375 in. (0.635 and 0.9525 cm) in diameter were considered and nozzle exit Reynolds Number varied from 10,000 to 60,000.The ratio of nozzle center to center distance to the nozzle diameter, given by Cn/D, of 2 and 3 were considered. The jet velocity was not too high, such that at a Mach Number less than 0.3, the flow was still incompressible. Jets issuing from an array of five and nine nozzles were studied. The effect of additional four nozzles was considered, on the central nozzle screened in the five nozzle array by four jets. The objective of the tests was to experimentally investigate the centerline velocity profiles, velocity profiles across the centerline, static pressure distribution across and along the centerline and spread of the jets in the free jet zone; and for the velocity profiles, pressure distribution and spread of the jets in the deflection and wall jet zones.
Among many other uses, jets are used to cool the internal surfaces of turbine vanes and blades. In order to develop adequate heat transfer correlations for this type of cooling, a knowledge of the jet flow characteristics is necessary. Flow parameters were measured along the centerline of the normal impinging array of jets and in the resulting wall jet, at the surface of the smooth, flat, lucite plate. Results obtained for single jets proved useful for explanation of the more complicated flow of an array of jets.
The flow behavior in the wall jet zone and the deflection zone were analysed experimentally. Except in the immediate vicinity of the target plate, impinging jets behave in many respects like free jets. Experimental investigation was also carried out for the boundary layer thickness at the stagnation points and in the wall jet region. This was the first systematic investigation of the flow characteristics of an array of free and impinging jets.
Recommended Citation
Sethi, Samir, "Experimental investigation of submerged, turbulent, array of air jets impinging on a flat plate" (1984). Theses. 3633.
https://digitalcommons.njit.edu/theses/3633
