Effect of Different Materials and Coolant Channel Configurations on the Performance of Actively Cooled Panels

The combustor liners of high speed combustion chamber are subjected to high thermal loads. Active cooling of such liners is seen as a viable option and research in this area is currently underway in many countries due to the advantages it offers. The main method of heat transfer is the regenerative cooling, where in coolant is passed through the channels provided in the combustion liner. But, the configuration of such liners has to be optimized in terms of providing desired cooling efficiency with the given mass flow rate of the coolant, so as not to carry the coolant more than required and keep the weight per unit area under control. The cooling efficiency is mainly dependent on several factors, which include the properties of material, dimensions of the cross-section of the flow, shape of the channel, mass flow rate of the coolant. For the current investigation different candidate high temperature materials and channel shape combinations are investigated for their thermal performance to effectively remove the high heat flux. The comparison brings out the most efficient material cum configuration suitable for application to the high speed combustion chamber. In the initial study, various configurations are verified based on minimum weight per unit area with the help of 1D MATLAB program and the results are further validated for the suitable configurations using ANSYS CFX. It was found that at high heat fluxes Nb-Cb752 can serve at lower mass flow rates. GRCop-84 material is found to compete with Nb-Cb752 in terms of the mass flow rate required. For a given mass flow rate, Inconel X-750 has the lowest weight per unit area compared to the other materials. Parabolic shape has been found to effective followed by Trapezoidal and rectangular shapes. So, it is important that the combination of the material and channel configuration play a significant role in the design of efficient heat exchanger of a high speed combustion chamber.