Flow and thermal transport of supercritical n-decane in square minichannel featuring uniformly spaced tetrakaidecahedron-shaped unit cells

Abstract

In the current study, a novel cooling channel configuration featuring periodically placed tetrakaidecahedron (TKD) unit cells is proposed and studied computationally. The concept can also be realized through the additive manufacturing process to mitigate the heat transfer deterioration and improve the overall thermal performance of combustor cooling channels with n-decane as the working fuel. The conjugate thermal performance of the TKD channel was investigated and compared with the corresponding smooth channel at 3 MPa operating pressure. Simulations were conducted at a fixed coolant mass flow rate of 2 g/s, wall heat flux of 1.5 MW/m2, and an inlet temperature of 423.15 K. TKD channel provided lower overall wall temperatures and higher heat transfer coefficient values than the smooth channel. Furthermore, the thermal performance of both the smooth and TKD channels were analyzed under accelerated flight conditions by employing accelerations ac=2 g, 4 g, and 6 g in the streamwise direction. For the smooth channel, with increase in the acceleration values, the peak temperature values were reduced, and the location of peak value shifted towards the channel outlet. The thermal performance of TKD channel was, however, not significantly influenced by the accelerated states, which ensures enhanced cooling performance at different operating conditions.