QUIZ 4

Steam is admitted to the cylinder of an engine in such a manner that the average pressure is 120 psi. The diameter of the piston is 10 in and the length of the stroke is 12 in. What is the hp of the engine when it is making 300 rpm?

• 171.5

• 173.2

• 175

• 174.4

A superheat steam Rankine Cycle has a turbine inlet conditions of 17.5 MPa and 530°C expand in a turbine to 0.007 MPa. The turbine and pump polytropic efficiencies are 0.9 and 0.7 MPa, respectively, pressure losses between the pump and the turbine inlet are 1.5 MPa. What should be the pump work in kJ/kg if the specific volume in the pump inlet is 0.001 m^3/kg?

• 17.3

• 37.3

• 27.3

• 47.3

Steam flows into a turbine at the rate of 10 kg/s and 10 kW of heat are lost from the turbine. Ignoring elevation and kinetic energy effects, calculate the power output from the turbine. Given: h1 = 2739 and h2 = 2300.5 kJ/kg.

• 4605 kW

• 4375 kW

• 4973 kW

• 4395 kW

A steam power plant has a turbine work of 654 kJ/kg and the pump work is 3 kJ/kg. If the mass flow rate is 18 kg/s, compute the power produced by the plant.

• 11772 kW

• 11718 kW

• 11826 kW

• 10440 kW

The energy input to the turbine is 2800 kJ/kg and the energy at the exit is 1400 kJ/kg, efficiency of the engine is 75% and power output at full load is 6000 kW. What is the turbine flow rate at full load in kg/kW-hr?

• 3.43

• 5.97

• 4.33

• 9.23

A Carnot engine operates using 527°C energy reservoir and a 27°C energy reservoir. The thermodynamic efficiency of this engine is?

• 50%

• 73.6%

• 62.5%

• 103%

A liquid dominated geothermal plant with a single flash separator receives water at 204°C. The separator pressure is 1.04 MPa. A direct-contact condenser operates at 0.034 MPa. The turbine has a polytropic efficiency of 0.75. For a cycle output of 50 MW, what is the mass flow rate of the well-water in kg/s?

Note: At 204°C, hf = 870.51 kJ/kg

At 1.04 MPa, hf = 770.38, hfg = 2009.2, hg = 2779.6, sg = 6.5729

At 0.034 MPa, hf = 301.40, hfg = 2328.8, sf = 0.9793, sfg = 6.7463

• 2871

• 186

• 2100

• 2444

A crack in the earth through which the geothermal substances pass.

• Magma

• Fumarole

• Steam Vent

• Geyser

This type of geothermal plant uses dry steam directly to drive the turbine.

• Dry Geothermal Power Plant

• Single Flash Geothermal Power Plant

• Double Flash Geothermal Power Plant

• Binary Geothermal Power Plant

An 18 MW geothermal plant has a generator efficiency and turbine efficiency of 90%. If the quality after throttling is 20% and each well discharges 400,000 kg/hr, compute the number of wells required to produce if the change of enthalpy at entrance and exit of turbine is 500 kJ/kg.

• 4 wells

• 5 wells

• 2 wells

• 3 wells