4.13 Refrigerant 134a enters the evaporator of a refrigeration system operating at steady state at -4°C and quality of 20% at a velocity of 7 m/s. At the exit, the refrigerant

is a saturated vapor at a temperature of -4°C. The evaporator flow channel has constant diameter. If the mass flow rate of the entering refrigerant is 0.1 kg/s, determine a. the diameter of the evaporator flow channel, in cm. b. the velocity at the exit, in m/s.