Supply channel heat transfer with simultaneous impingement jet array cooling and crossflow cooling
Date of Award
Master of Science in Engineering (MSE)
Mechanical and Aerospace Engineering
Jason T. Cassibry
Heat--Transmission--Measurement., Nusselt number., Liquid crystals--Thermographic methods.
Experimental data are provided for four different sets of experimental conditions for the coolant-side of a double wall cooled effusion test plate. Employed are three different passages for main flow, cross flow, and impingement flow. Coolant is supplied through the cross flow channel and by means of an impingement jet array to the coolant-side of the effusion test plate. This coolant then supplies all effusion hole entrances. The impingement plate and effusion plate both contain six staggered rows of 10 holes per row, where impingement holes are offset so that each is located between effusion hole entrance locations. Installed within the effusion test plate on the coolant-side is a custom-manufactured etched-foil heater, which is employed to provide a uniform surface heat flux thermal boundary condition. The inlet and outlet of the main flow passage are configured with a contraction ratio of 4 to provide a strong favorable pressure gradient with streamwise development. Liquid crystal thermography is employed to measure spatially-resolved distributions of surface Nusselt number values along the cold-side of the effusion plate. Of particular interest is the simultaneous use of cross flow and impingement flow, as associated Reynolds numbers and mass flow rates are varied. Resulting data are compared to measured data (from previous investigations) using arrangements which employed cooling air provided either by a cross flow only configuration, or by an impingement only arrangement. In the present study, surface Nusselt number distributions are strongly affected by distributions and concentrations of coolant distributed across the surface on the coolant-side of the effusion plate. Here, higher surface Nusselt number values indicate increased surface heat transfer augmentation, and improved cooling and thermal protection along on the surface. Results indicate that the impingement-only arrangement provides the most effective distribution of coolant along the cold-side of the effusion test plate, when compared to the combination arrangements and to the cross flow only arrangements. As initial blowing ratio and impingement flow Reynolds number increase, while cross flow Reynolds number is held constant, impingement flow begins to overpower the cross flow, which leads to the higher Nusselt number values for particular test cases where cross flow is constant and impingement flow varies.
Ritchie, David, "Supply channel heat transfer with simultaneous impingement jet array cooling and crossflow cooling" (2019). Theses. 304.