Chapter 6, Problem 6.120P

An oil pump operating at steady state delivers oil at a rate of 12 lb/s through a 1-in.-diameter exit pipe. The oil, which can be modeled as incompressible, has a density of 55 lb/ft3 and experiences a pressure rise from inlet to exit of 40 lbf/in². There is no significant elevation difference between inlet and exit, and the inlet kinetic energy is negligible. Heat transfer between the pump and its surroundings is negligible, and there is no significant change in temperature as the oil passes through the pump. Determine the velocity of the oil at the exit of the pump, in ft/s, and the power required for the pump, in hp.

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A water pump operating at steady state has 76 mm diameter inlet and exit pipes, each at the same elevation. The water can be modeled as incompressible and its temperature remains constant at 20°C. For a power input of 1.5 kW, determine the pressure rise from inlet to exit, in kPa at the volumetric flow rate of A m/s (A=0.015 m/s, 0.017 m/s, 0.02 m/s). Plot the A- the pressure rise from inlet to exit in graph.

12

Liquid flows at steady state at a rate of 2 lb/s through a pump, which operates to raise the elevation of the liquid 100 ft from control volume inlet to exit. The liquid specific enthalpy at the inlet is 40.09 Btu/lb and at the exit is 40.94 Btu/lb. The pump requires 3 Btu/s of power to operate. If kinetic energy effects are negligible and gravitational acceleration is 32.174 ft/s2, the heat transfer rate associated with this steady state process is most closely:   A) 2.02 Btu/s from the liquid to the surroundings. B) 3.98 Btu/s from the surroundings to the liquid. C) 4.96 Btu/s from the surroundings to the liquid. D) 1.04 Btu/s from the liquid to the surroundings.

An oil pump operating at steady state delivers oil at a rate of 6 kg/s through a 2.5-cm- diameter exit pipe. The oil, which can be modeled as incompressible, has a density of 1360 kg/m³ and experiences a pressure rise from inlet to exit of 2.75 bar. There is no significant elevation difference between inlet and exit, and the inlet kinetic energy is negligible. Heat transfer between the pump and its surroundings is negligible, and there is no significant change in temperature as the oil passes through the pump. a. Determine the velocity of the oil at the exit of the pump, in m/s. b. Determine the power required for the pump, in W. Oil Pump Mflow=6kg/s Poil 1360 kg/m³ P2-p1-2.75 bar T₂-T₁=0 D=2.5 cm

T-7

A turbine operating under steady-flow conditions receives steam at the following state: pressure, 13.8 bar; specific volume 0143 m3/kg, and velocity 30 m/s. The state of the steam leaving the turbine is as follows: pressure 0.35 bar, specific volume 4.37 m3/kg, and velocity 90 m/s. The difference in elevation is negligible. Heat is rejected to the surroundings at the rate of 0.25 kW, the turbine develops 103 kW of power and the rate of steam flow through the turbine is 0.5 kg/s. Calculate the change in internal energy of the steam

5. Air enters a compressor at a rate of 0.5 Kgs¹ with a velocity of 6.4 ms', specific volume 0.85 m³Kg¹ and a pressure of 1 bar. It leaves the compressor at a pressure of 6.9 bar with a specific volume of 0.16 m³Kg¹ and a velocity of 4.7 ms¹. The internal energy of the air at exit is greater than that at entry by 85 KJKg'. The compressor is fitted with a cooling system which removes heat at a rate of 60 KJs¹. Calculate the power required to drive the compressor and the cross- sectional areas of the inlet and outlet pipes.