(4) A steady flow for refrigerant R134a enters a 35 cm diameter pipe at 200 kPa and 30 °C with a velocity of 6 m/s. The refrigerant is heated along the

exterior walls of the pipe via electrical resistive heaters, exiting the pipe at 180 kPa and 60 °C. Note: There was a slight pressure loss due to friction between the fluid flow and the pipe walls. However, in some applications we can assume isobaric operation of the steady flow system. Determine the following, Part A: the volume flow rate of the refrigerant at the inlet Part B: the mass flow rate of the refrigerant through the pipe 1 Part C: using an assumption of constant density, estimate the velocity and volumetric flow rate at the exit. Based on the properties you found at state 1 and state 2, comment on the limitations of this assumption. Q 2 Part D: Calculate the heat flow rate (kW) delivered by the electrical coils assuming 1) the fluid exits at the recorded 180 kPa and 2) the flow remains isobaric through the system. Calculate the percent difference in the calculated heat flow rate between 1 and 2. Describe the impact of the isobaric assumption on the calculated value. Note: do not assume constant density anymore, that was just for part C.