Chapter 7, Problem 7.131EP

I have already found the enthalpies for this problem I just need to find the mass flowrate for the air h1 = 317.549 kJ/kg h2 = 114.245 kJ/kg h3 = 0.0159723 kJ/kg h4 = 37.2487 kJ/kg

Consider a diffuser operating at steady-state. Air flows in with a velocity of 300m/s, a pressure of 1 bar, and a temperature of 70 ºC. The outlet is at 1.5 bar and 107 ⁰C.What is the exit velocity? What is the ratio of exit area to the inlet area of the diffuser?

A pump is used to circulate hot water in a home heating system. Water enters the well-insulated pump operating at steady state at a rate of 0.42 gal/min. The inlet pressure and temperature are 14.7 lbf/in.?, and 180°F, respectively; at the exit the pressure is 60 Ibf/in.? The pump requires 1/25 hp of power input. Water can be modeled as an incompressible substance with constant density of 60.58 Ib/ft and constant specific heat of 1 Btu/lb. °R. Neglecting kinetic and potential energy effects, determine the temperature change, in °R, as the water flows through the pump. AT = i °R

A pump is used to circulate hot water in a home heating system. Water enters the well-insulated pump operating at steady state at a rate of 0.42 gal/min. The inlet pressure and temperature are 14.7 Ibf/in.?, and 180°F, respectively; at the exit the pressure is 120 Ibf/in.? The pump requires 1/ 15 hp of power input. Water can be modeled as an incompressible substance with constant density of 60.58 lb/ft³ and constant specific heat of 1 Btu/lb · °R. Neglecting kinetic and potential energy effects, determine the temperature change, in °R, as the water flows through the pump.

a. Air at 8 bar 100°C flows in a duct of 15 cm diameter at rate of 150 kg/min. It is throttled by upto 4 bar pressure. Determine the velocity of air after throttling and also show that enthalpy constant before and after throttling. b, Ans. 37.8 m/s 1. Determine the power required by a compressor designed to compress atmospheric through inlet area of 90 cm? with velocity of 50 m/s and leaves with velocity of 120 m/s from exit area of 5 cm?. Consider heat losses to environment to be 10% of power input to compressor. Ans. 50.4 kw C' Determine the power available from a steam turbine with following details; Steam flow rate = 1 kg/s Velocity at inlet and exit = 100 m/s and 150 m/s Enthalpy at inlet and exit = 2900 kJ/kg, 1600 k]/kg Change in potential energy may be assumed negligible. Ans. 1293.75 kw d. Determine the heat transfer in emptying of a rigid tank of 1 m² volume containing air at 3 bar and 27°C initially. Air is allowed to escape slowly by opening a valve until the pressure in…

3. Helium expands polytropically through a turbine according to the process pV15 = C. The inlet temperature is 1000 K, the inlet pressure is 1000 kPaa, and the exit pressure is 150 kPaa. The turbine produces 10 000 kW. Determine the mass flow rate of helium. For helium, M = 4 kg/kgmol and k = 1.666.

Air at 15 degree Celsius and 95 kpa enters the diffuser of a jet engine and steadily with a velocity of 250 m/s. The inlet area of the diffuser is 0.5 m^2. The air leaves the diffuser with a velocity that is very small compared with the inlet velocity. Find the mass flow of air, temperature of air leaving diffuser, power and rate of heat transfer within diffuser.

55 kmol per hour of air is compressed from P1 = 1 bar to P2 = 6.1 bar in a steady flow compressor. Delivered mechanical power is 98.9 kW. Temperatures and velocities are: T1 = 301K   T2 = 520 K,   u1 = 10.8 m/s  and u2 = 3.8 m/s.  Estimate the rate of heat transfer from the compressor in kW, 3 decimal values. Assume that Cp = 7/2R and that enthalpy is independent of pressure.

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