MIXED CONVECTIVE RAREFIED FLOWS WITH SYMMETRIC AND ASYMMETRIC HEATED WALLS

Mixed convection gaseous slip flows in an open-ended vertical parallel-plate channel with symmetric and asymmetric wall temperatures are numerically investigated. Buoyancy effects on developing and fully developed solutions are studied by solving the Navier-Stokes and energy equations using a control volume technique and SIMPLE algorithm. The velocity and temperature fields are examined for different values of Knudsen number, mixed convection parameter, and temperature ratio. It is found that decreasing temperature ratio leads to higher velocity slip along this wall. Moreover, the friction coefficient increases with increasing mixed convection parameter on the hot wall, whereas it decreases on the cold wall. It is also noticed that with an increase in mixed convection parameter, the net heat absorbed by the fluid becomes higher and the Nusselt number increases. Furthermore, the centerline pressure drops in the early sections of the channel due to the dominance of the viscous effects; however, it builds up later along the channel, when the buoyancy forces gain weight and play the dominant role.