Refrigerant 134a enters the evaporator of a refrigeration system operating at steady state at -8°c and quality of 15% at a velocity of 7 m/s. at the exit, the refrigerant is a saturated vapor at a temperature of -8°c. the evaporator flow channel has constant diameter. if the mass flow rate of the entering refrigerant is 0.4 kg/s, determine: (a) the diameter of the evaporator flow channel, in cm. (b) the velocity at the exit, in m/s.