TABLE OF CONTENTS Maxwell (1879) studied the near-wall behavior of fluid flow of large Kn and proposed that there might be a finite slip of velocity and a jump of temperature for gaseous fluid when the mean free path is large compared to the flow dimensions. The large gradients of temperature and velocity may affect the transport of heat and momentum in a manner that is different from those observed in larger systems. As the number of industrial and scientific devices using microelectromechanical systems (MEMS) increases, a detailed understanding of the heat transfer in microchannel flows is becoming increasingly important for an accurate prediction of their performance and for a better design. In Chap. 9, low-speed microflows were described. In this chapter, the heat transfer characteristics of two-dimensional microchannels of high-speed inflows at atmospheric conditions, as opposed to vacuum conditions (Yasuhara et al. 1989), are examined. Particularly, the effects of Kn on the wall heat flux are investigated in detail. The value of Kn is changed by varying the channel height, while keeping the aspect ratio of channel constant. The bow shock structure, temperature distribution, and net heat flux on the wall for a range of Kn are examined. Detailed studies of shocks in and around microscale devices can be found in Dlott (2000), Ohashi et al. (2001), and Brouillette (2003).
The DSMC method is used to simulate the heat transfer in two-dimensional microchannel flows near the atmospheric condition. The two-dimensional simulations allow a better use of...
