Mastery Exam 01 – PIPE – Problems

A waste heat recovery boiler produces 4.8 MPa (dry saturated) steam from 104°C feedwater. The boiler receives energy from 7 kg/sec of 954°C dry air. After passing through a waste heat boiler, the temperature of the air is has been reduce to 343°C. How much steam in kg is produced per second? Note: At 4.80 MPa dry saturated, h = 2796.

A diesel electric plant supplies energy for Meralco. During a 24–hr period, the plant consumed 240 gallons of fuel at 28°C and produced 3930 kw-hr. Industrial fuel used is 28 ˚API and was purchased at P30 per liter at 15.6°C. What is the cost of fuel be to produce one kw-hr?

In a gas turbine unit, air enters the combustion chamber at 550 kPa, 277°C and 43 m/s. The products of combustion leave the combustor at 511 kPa, 1004°C and 180 m/s. Liquid fuel enters with a heating value of 43,000 kJ/kg. For fuel-air ratio of 0.0229, what is the combustor efficiency of the unit in percent?

The specific speed of turbine is 85 rpm and running at 450 rpm. If the head is 20 m and generator efficiency is 90%, what is the maximum power delvered by the generator?

In Francis turbine, the pressure gage leading to the turbine casing reads 380 kPa. The velocity of water entering the turbine is 8 m/sec, if the net head of the turbine is 45 m, find the distance from center of spiral casing to the tailrace.

A turbine has a mechanical efficiency of 93%, volumetric efficiency of 95% and total efficiency of 82%. If effective head is 40 m, find the total head.

A pelton type turbine has a 25 m head friction loss of 4.5 m. The coefficient of friction head loss (from Morse) is 0.00093 and penstock length of 80 m. What is the penstock diameter?

In a 9,000 kW hydro–electric plant the over-all efficiency is 88% and the actual power received by the customer is 110,000 kW-hrs for that day. What is the secondary power could this plant deliver during the entire day?

A Pelton type turbine was installed 30 m below the head gate of the penstock. The head loss due to friction is 12 percent of the given elevation. The length of penstock is 100 m and coefficient of friction is 0.00093. Determine the power output in kW. (Using Morse equation)

Water flows steadily with a velocity of 3.05 m/s in a horizontal pipe having a diameter of 25.24 cm. At one section of the pipe, the temperature and pressure of the water are 21°C and 689 kPa; respectively. At a distance of 304.8 m downstream, the pressure is 516.9 kPa. What is the friction factor?

A hydro-electric plant having 30 sq. km reservoir area and 100 m head is used to generate power. The energy utilized by the consumers who load is connected to the power plant during a five-hour priod is 13.5×106 kwh. The overall generation efficiency is 75%. Find th fall in the height of water in the reservoir after th 5-hour period.

The gas density of the chimney is 0.75 kg/m³ and air density of 1.15 kg/m³. Find the driving pressure if the height of chimney is 63.71 m.

The actual velocity of the gas entering in a chimney is 8 m/sec. The gas temperature is 25°C with the gas constant of 0.287 kJ/kg-˚K. Determine the gas pressure for a mass of gas is 50,000 kg/hr and chimney diameter of 1.39 m.

A steam generator with economizer and air heater has an overall draft loss of 25.78 cm of water. If the stack gases are at 177°C and if the atmosphere is at 101.3 kPa and 26°C, what theoritical height of stack in meters is needed when no draft fan are used? Assume that the gas constant for the flue gases is the same as that for air.

A foundation measures 12 ft x 14 ft x 16 ft. Find the number of sacks of cement needed for 1:2:4 mixture.

A rectangular foundation cross–section has a bed plate dimension of 8 ft x 10 ft. The uniform clearance on each side 1 ft. The height of the foundation is 4.5 ft. If the weight of the steel bar reinforcements needed is 1/2 % of the weight of foundation, find the weight of steel bars. Use concrete density of 2400 kg/m³.

The initial condition of air in an air compressor is 98 kPa and 27°C and discharges air at 450 kPa. The bore and stroke are 335 mm and 381 mm, respectively with percent clearance of 8 % running at 300 rpm. Find the volume of air at suction.

An air compressor has a suction volume of 0.35 m³/sec at 97 kPa and discharges to 650 kPa. How much power saved by the compressor if there are two stages?

A two stages air compressor has an intercooler pressure of 4 kg/cm². what is the discharge pressure of if suction pressure is 1 kg/ cm²?

A two-stage compressor air at 100 kPa and 22°C discharges to 750 kPa. If intercooler intake is 105°C, determine the value of n.

A single acting air compressor has a volumetric efficiency of 89%, operates at 500 rpm. It takes in air at 100 kPa and 30°C and discharges it at 600 kPa. The air handled is 8m³ /min measured at discharge condition. If compression is isentropic, find mean effective pressure in kPa.

A water-jacketed air compressor handles 0.343 m³/s of air entering at 96.5 kPa and 21°C and leaving at 480 kPa and 132°C; 10.9 kg/hr of cooling water enters the jacket at 15°C and leaves at 21°C. Determine the compressor brake power.

A double suction centrifugal pump delivers 20 ft³/sec of water at a head of 12 m and running at 650 rpm. What is the specific speed of the pump?

Determine the number of stages needed for a centrifugal pump it is used to deliver 400 gal/min of water and pump power of 15 hp. Each impeller develops a head of 30 ft.

The suction pressure of a pump reads 3 in of mercury vacuum and discharge pressure needs 140 psi is use to deliver 120 gpm of water with specific volume of 0.0163 ft³/lb. Determine the pump work.

A submersible pump delivers 350 gpm of water to a height of 5 ft from the ground. The pump were installed 150 ft below the ground level and a draw down of 8 ft during the operation. If the water level is 25 ft above the pump, determine the pump power.

A vacuum pump is used to drain a flooded mine shaft of 20°C water. The pump pressure of water at this temperature is 2.34 kPa. The pump is incapable of lifting the water higher than 16m. What is the atmospheric pressure?

A submersible, multi-stage, centrifugal deep well pump 260 gpm capacity is installed in a well 27 ft below the static water level and running at 3000 rpm. Drawdown when pumping at rated capacity is 10 ft. The pump delivers the water into a 25000 gallons capacity overhead storage tank. Total discharge head developed by pump, including friction in piping is 243 ft. Calculate the diameter of the impeller of this pump in inches if each impeller diameter developed a head of 38 ft.

A fan draws 1.42 m³/sec of air at a static pressure of 2.54 cm of water through a duct 300 mm diameter and discharges it through a duct of 275 mm diameter. Determine the static fan efficiency if total fan mechanical is 75% and air measured at 25°C and 760 mmHg.

A water cooler uses 50 lb/hr of melting ic to cool running water from 80°F to 42°F. Based on the inside coil area, U1=110 BTU/hr-ft²-F. Find the gpm of water cooled.

The charge in a Diesel engine consists of 18.34 grams of fuel, with lower heating value of 42,571 kJ/kg, and 409 grams of fuel and products of combustion. At the beginning of compression, t1=608C. Let rk =14. for constant Cp=1.11 kJ/kg-C, what should be the cut-off ration in the corresponding ideal cycle?

The gain entropy during isothermal nonflow process of 5 lb of air at 60°F is 0.462 BTU/R. Find the V₁/V₂.

An auditorium seating 1500 people is to be maintained at 80°F dry bulb and 65°F wet bulb temperature when outdoor air is at 91°F dry bulb and 75°F wet bulb. Solar heat load is 110,000 BTU/hr and supply air is at 60°F, determine the amount of supply air.

In a Brayton cycle that operates between temperature limits of 300˚K and 1773˚K with k =1.4, determine the temperature at the end of the compression (isentropic) for maximum work of the cycle.

At 35% solution leaves the absorber and 30% solution enters the absorber. The heat removed from the absorber by cooling water is 547.6 BTU and ammonia is superheated by 10 ˚. Find the pound per pound of ammonia gas from the evaporating coils.

A Carnot refrigeration system operates at Tmax/Tmin= 1:5. Find the kW per ton of refrigeration.

Assume 8 ft² of air at 100 psi, 100°F are compressed isothermally to a volume of 2 ft³. for each of end states the process, find the bulk modulus.

An empty, open can is 30 cm high with a 15 cm diameter. The can, with the open end down, is pushed under water with density of 1000 kg/m³. Find the water level in the can when the top of the can is 50 cm below the surface.

A cylindrical pipe with water flowing downward at 0.03 m³/s having top diameter of 0.08, bottom diameter of 0.04 m and height of 1.5 m. Find the pressure between the pipe.

Determine the size of pipe which will deliver 8 liters of medium oil (v = 6.10 x 10 -6 m²/s) assuming laminar flow conditions.

The type of flow occupying in a 1 cm diameter pipe which water flows at a velocity of 2.50 m/s. Use v = 1.13 x 10-6 m²/s of water.

What force is exerted by water jet 60 mm diameter if it strikes a wall at the rate of 15 m/s?

A 300 mm diameter pipe discharges water at the rate of 200 li/s. Point 1 on the pipe has a pressure of 260 kPa and 3.4 m below point 1 is point 2 with a pressure of 300 kPa. Compute the head loss between points 1 and 2.

Water flowing at the rate of 10 m/s from an orifice at bottom of a reservoir. Find the pressure at the bottom of reservoir.

Steam flows through a nozzle at 400°C and 1 MPa (h=3263.9 kJ/kg) with velocity of 300 m/s. Find the stagnation enthalpy.

Air flows through a nozzle at a speed of 350 m/s. Find stagnation enthalpy if entrance temperature is 200°C.

Carbon dioxide flows through a nozzle with a speed of 00 m/s. Compute the dynamic temperature.

Carbon dioxide flows through a nozzle with a speed of 380 m/s. The entrance condition of nozzle is 250°C and 1200 kPa. Find the stagnation pressure.

Air enters a diffuser with a velocity of 200 m/s. Determine the velocity of sound if air temperature is 30 ˚ C.

Air flows through a nozzle with temperature of entrance of 420 ˚K stagnation temperature of 468 ˚K. Find the mach number.