Analysis of chamber effect on intermittent pulsation

Abstract

A numerical study was conducted to seek an optimized dimension of jet chamber in the pulsating impinging flow. The flow and heat transfer effect of the pulsation flow through a jet chamber was investigated. The numerical results indicate that heat transfer effective enhances near the stagnation region for the intermittent pulsed flow with jet chamber compared to that without jet chamber. Simulations of the flow through a jet chamber show that the heat transfer rate on the impingement surface is highly dependent on the velocity at the position which is really close to target surface. Examination of the velocity field suggests that the velocity exists a maximum value as the axis distance increases. In addition, the velocity at the jet hole is enlarged by the jet chamber due to the entrainment effect, and the velocity is amplified even greater as the size of the jet chamber becomes bigger. Nevertheless, the velocity declines quickly while the flow axis distance is more than a certain range, leading to poor heat transfer. Thus, intermittent pulsed flow with jet chamber is suggested as a method of improving heat transfer by employing larger dimensions of jet chamber for appropriate jet-to-surface spacing.