Question

Refrigerant-134a enters a 28-cm diameter pipe steadily at 200 kPa and 20°C with a velocity of 5 m/s. The refrigerant gains heat as it flows and leaves the pipe at 180 kPa and 40°C. Determine (a) the volume flow rate of the refrigerant at the inlet, (b) the mass flow rate of the refrigerant, and (c) the velocity and volume flow rate at the exit.

Answer 1

Refrigerant-134a flows through a pipe. Heat is supplied to R-134a. The volume flow rates of air at the inlet and exit, the mass flow rate, and the velocity at the exit are to be determined.

Properties: The specific volumes of R-134a at the inlet and exit are (Table A-13)

Analysis: (a) (b) The volume flow rate at the inlet and the mass flow rate are

(c) Noting that mass flow rate is constant, the volume flow rate and the velocity at the exit of the pipe are determined from