PIPE 1_02

100問 • 1年前

問題一覧

Brine enters a circulating brine cooler at the rate of 80 m%3/hr at -8 degC, specific heat of brine is 1.072 kj/kg-K and specific gravity of 1.12. determine the tons of refrigeration.

D. 56.9 TR

At 1.8 Mpa, mixture steam and water has an entropy of 3 KJ/kg Deg K. find the enthalphy of the mixture.

D. 1,162.40 KJ/kg

Mixture with 70% quality at 500kpa is heated isothermally until its pressure is 300kpa. Find the heat added during the process.

A. 745.92 KJ/kg

A tank contains exactly one kilogram of water consisting of liquid and vapor in equilibrium at Mpa. If the liquid contains one-third and the remaining is vapor of the volume of the tank, what is the enthalpy of the contents of the tank?

C. 785.92 KJ/kg

Water substance at 70 bar and 65 degC enters a boiler tube of constant inside diameter of 25mm. the water leaves the boiler tube at 50 bar and 700degK at velocity of 150m/s/ calculate the inlet velocity(m/sec)

B. 2.51

Water substance at 70 bar and 65 degC enters a boiler tube of constant inside diameter of 35mm. the water leaves the boiler tube at 50 bar and 700degK at velocity of 100m/s/ calculate the inlet volume flow (li/sec)

D. 1.609

Steam leaves an industrial boiler at 827.4 Kpa and 171.6 deg. C. A portion of the steam is passed through a throttling calorimeter and is exhausted to the atmosphere when the calorimeter pressure is 101.4 Kpa. How much moisture does the steam leaving the boiler contain if the temperature of the steam at the calorimeter is 115.6 Deg. C.

B. 3.08%

A throttling is connected to the desuperheated steam line supplying steam to the auxiliary feed pump on a ship. The line pressure measrues 2.5 Mpa. The calorimeter pressure is 110 Kpa and 150 deg. C. determine the entropy of the steam line.

B. 6.2 KJ/Kg-k

Atmospheric pressure at boils 212 deg. F. At the vacuum pressure at 24 in. Hg, the temperature is 142 deg F. Find the boiling temperature when the pressure is increased by 40 psia from atmospheric.

A. 449.42 F

A certain coal has the following ultimate analysis: C = 69% N2 = 5% H2 = 2.5% S = 7% Determine the amount of oxygen if the heating value of fuel is 26,961.45 KJ/Kg.

D. 4.5 %

A diesel engine consumed 946 liters of fuel per day at 35 deg. C. if the fuel was purchased at 15.6 deg. C and 30 deg. API at P29.00/li, determine the cost of fuel to operate the engine per day.

D. P 27,127.76

A cylindrical tank 4m long and 3m diameter is used for oil storage. How many days can the tank supply the engine having 27 deg. API with fuel consumption of 60 kg/hr?

A. 17.53

A logging firm in Isabella operates a Diesel Electric Plant to supply it’s electric energy requirements. During a 24 hour period, the plant consumed 250 gallons of fuel at 80 deg. F and produced 2900 KW-hrs. Industrial fuel used is 30 deg. API and was purchased at P30.00/li at 60 deg. F. Determine the overall thermal efficiency of the plant.

C. 28.00 %

The dry exhaust gas from oil engine has the following gravimetric analysis : CO2 = 21.6% O2 = 4.2% N2 = 74.2% Specific heats at constant pressure for each component of the exhaust gas in Kcal/kg-C are: CO2 = 0.203. O2 = 0.219 N2 = 0.248 Calculate the specific gravity if the molecular weight of air is 28.97 kg/lg-mol

C. 1.055

A bituminous coal has the following composition: C= 71.5% H = 5.0% O = 7.0% N = 1.3% S = 3% Ash = 7.6% W = 3.4% Determine the theoretical weight of Nitrogen in lb/lb of coal

B. 7.526

A gaseous fuel mixture has a molal analysis: H2 = 14 % CH4 = 3 % CO = 27 % O2 = 0.6% CO2 = 4.5% N2 = 50.9% Determine the air-fuel ratio for complete combustion on molal basis.

C. 1.233

A volumetric analysis of a gas mixture is as follows: CO2 : 12% O2 : 4% N2 : 80% CO4 : 4% What is the percentage of CO2 on a mass basis?

A. 17.55 %

A diesel cycle has a cut off ratio of 2.5 and expansion ratio of 4. Find the clearance of cycle.

C. 11.11 %

A dual cycle has an initial temperature of 30C. the compression ratio is 6 and the heat addition at constant volume process is 600kj/kg. if cut off ratio is 2.5, find the maximum temperature of the cycle.

B. 3365.50 deg C

A three stages air compressor compresses air from 100kpa to 1000kpa. Find the intercooler pressure between the first and second stage.

D. 215.44 kpa

A 10—stages air compressor compresses air from 100kpa to 800kpa. Find the intercooler pressure between the first and second stage.

C. 123.11 kpa

A 3 stages air compressor compresses air from 100kpa to 700kpa. Find the intercooler pressure between 2nd and 3rd stage

A. 365.88 kpa

Carnot cycle a,b,c are connected in series so that the heat rejected from a will be the heat added to B an heat rejected from b will be added to c. each cycle operates between 30degC and 400degC. If heat added to A is 1000kw, find the work output of C.

A. 111.4 kw

Air is compressed adiabatically from 30degC to 100degC. If mass of air being compressed is 5kg, Find the change of entropy?

C. 0

Two kilogram of air in a rigid tank changes its temperature from 32degC to 150degC. Find the work done during the process.

D. 0

Determine the atmospheric pressure at a location where barometric reading is 740mm Hg and gravitational acceleration is g = 9.7m/s^2. Assume the temperature of mercury to be 10 deg.C at which the density is 13,570 kg/m^3.

B. 97.41 kpa

The barometer of a mountain hiker reads 930mbars at the beginning of a hiking reads 780 mbar at the end. Neglecting the effect of altitude on local gravitational acceleration, determine the vertical distance climbed. Assume g = 9.7 m/s^2.

B. 1289.00 m

The lower half of a 10 m high cylindrical container is filled with water and upper half with oil that has SG= 0.85. determine the pressure difference between the top and bottom of the cylinder.

A. 90.74 Kpa

An ideal gas at 0.80 atmosphere and 87degC occupies 0.450 liter. How many moles are there is the sample? (R=0.0821 liter- atm/mole-K)

C. 0.0122 mole

A certain gas at 101.325 Kpa and 10 degC whose volume is 2.83 m^3 are compressed into a storage vessel of 0.31m^3 capacity. Before admission, the storage vessel contained the gas at a pressure and temperature of 137.8 Kpa and 26 degC; after admission the pressure has increased to 1171.8 Kpa. What should be the final temperature of the gas in the vessel in kelvin?.

D. 314.2

A superheat steam Rankine cycle has turbine inlet conditions of 17.5 MPa and 530 degC expands in a turbine to 0.007 Mpa. The Turbine and pump polytrophic efficiencies are 0.85 and 0.75 respectively, pressure losses between pump and turbine inlet are 1.5 Mpa. What should be the pump work in Kj/kg?

C. 25.32

In an open feedwater heater for a steam plant, saturated steam at 7 bar is mixed sub- cooled liquid at 7 bar and 25 degC. Just enough steam is supplied to ensure that the mixed steam leaving the heater will be saturated liquid at 7 Bar when heater efficiency is 95%. Calculate the mass flow rate of sub-cooled liquid if steam flow rate is 0.865 kg/s.

C. 2.869 kg/s

A steam condenser receives 10 kg/s of steam with an enthalpy of 2770 kj/kg. steam condenses into a liquid and leaves with an enthalpy of 160 kj/kg. cooling water passes through the condenser with temperature increases from 13 DegC to 24 DegC. Calculate the water flow rate in Kg/s.

B. 567

Steam expands adiabatically in a turbine from 200 Kpa, 400 DegC to 400 Kpa, 250 DegC. What is the effectiveness of the process in percent assuming an atmospheric pressure of 18 DegC. Neglect changes in kinetic and potential energy.

D. 79.46

A heat exchanger was installed purposely to cool 0.50 kg of gas per second. Molecular weight is 32 and k = 32. The gas is cooled from 150 degC to 80 DegC. Water is available at the rate of 0.30 kg/s and at a temperature of 5 degC. Calculate the exit temperature of the water in degC.

A. 44.86

A 350 mm x 450 mm steam engine running at 280 rpm has an entrance steam condition of 2 MPa and 230 degC and exit 0.1 Mpa. The steam consumption is 2000 kg/hr and mechanical efficiency is 85% if indicated mean effective pressure is 600 Kpa, determine brake thermal efficiency.

B. 15.25 %

A steam turbine receives 5,000 kg/hr of steam at 5 Mpa and 400 DegC and velocity of 30 m/sec. It leaves the turbine at 0.006 Mpa and 85% quality and velocity of 15m/sec. radiation loss is 10,000 Kj/hr. find the KW developed.

C. 1373.60

A steam turbine with 85% stage efficiency receives steam at 7 Mpa and 550 degC and exhaust as 20 Kpa. Determine the turbine work.

D. 1,054.95 Kj/kg

A steam turbine with 80% stage efficiency receives steam at 7 Mpa and 550 DegC and exhaust as 20 Kpa, determine the quality at exhaust.

A. 96.96 %

18,000 KW geothermal plant has a generator efficiency and turbine efficiency of 90% and 80%, respectively. The quality after throttling is 20% and each well discharges 400,000 kg/hr, determine the number of wells are required to produce if the change of enthalpy at entrance and exit of turbine is 500 kj/kg.

B. 2 wells

A liquid dominated geothermal plant with a single flash separator receives water at 204 DegC. 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 60 MW, what is the mass flow rate if the wall-water in kg/s?

A. 2,933

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 a density of 1000 kg/m^3. Find the water level in the can when the top of the can is 50 cm below the surface.

B. 12.12 cm

A cylindrical pipe with water flowing downward at 0.03 m^3/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.

C. 252.44 Kpa

Determine the size of pipe which will deliver 8 liter of medium oil (c = 6.10 x 10 ^-6 m^2/s) assuming laminar flow conditions

D. 835 mm

The type of flow occupying in a 1 cm diameter pipe which water flows at a velocity of 2.50m/s. Use v = 1.13 x 10^- 6 m^2/s for water.

A. Turbulent

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

A. 636.17 N

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.

D. 1.87 m

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

C. 50 Kpag

Steam flows through a nozzle at 400 deg. C and 1 Mpa (h = 3263.9 KJ/kg) with velocity of 300 m/s. find the stagnation enthalpy.

D. 3309 KJ/kg

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

C. 261.25 deg C

Carbon dioxide flows through a nozzle with a speed of 400 m/s. Compute the dynamic temperature.

B. 94.56 K

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

A. 2,136.34 Kpa

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

C. 369 m/s

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

B. 0.754

Air at 300 deg. K and 200 Kpa is heated at constant pressure to 600 deg. K. determine the change of internal energy.

D. 215.58 KJ/kg

An insulated rigid tank initially contains 1.5 lb of helium at 60 deg F and 50 psia. A paddle wheel with power rating of 0.02 hp is operated within the tank for 30 min. Determine the final temperature.

C. 179.22 deg. F

A 4 m^2 asphalt pavement with emissivity of m0.85 has a surface temperature of 50 deg. C. Find the maximum rate of radiation that can be emitted from the surface.

D. 2,098.32 watts

An aluminum pan whose thermal conductivity is 237 W/m-C has a flat bottom whose diameter is 20 cm and thickness 0.4 cm. heat is transferred steadily to boiling water in the pan through its bottom at a rate of 500 watts. If the inner surface of the bottom of the pan is 105 deg. C, determine the temperature of the surface of the bottom of the pan

B. 105.27 deg. C

For a heat transfer purposes, a standing man can be modeled as a 30 cm diameter, 170 cm long vertical cylinder with both the top and bottom surfaces insulated and with the side surface at an average temperature of 34 deg. C. for convection heat transfer coefficient of 15 W/m^2-C, determine the rate of heat loss from this man by convection in an environment at 20 deg. C.

C. 336.46 watts

A 5 cm diameter spherical ball whose surface is maintained at a temperature of 70 deg. C is suspended in the middle of a room at 20 deg. C. if the convection heat transfer coefficient is 15 W/m^2-C and the emissitivity of the surface is 0.8, determine the total heat transfer from the ball.

B. 32.77 watts

A frictionless piston-cylinder device and a rigid tank contain 1.2 kmol of ideal gas at the same temperature, pressure and volume. Now heat is transferred, and the temperature of both system is raised by 15 deg. C. the amount of extra heat that must be supplied to the gas in the cylinder that is maintained at constant pressure.

D. 150 KJ

A supply of 50 kg of chicken at 6 degC contained in a box is to be frozen to -16 degC in a freezer. Determine the amount of heat that needs to be removed. The latent heat of the chicken is 247 kj/kg and its specific heat is 32 kj/kg-C above freezing and 1.77 Kj/kg- C below freezing. The container box is 5 kg and the specific heat of the box material is 1.4 kj/kg-C. also the freezing temperature of chicken is -2.8 C.

A. 15,206.4 KJ

Water is being heated in a closed pan on top of a range while being stirred by a paddle wheel. During process, 30 kJ of heat is transferred to the water, and 5 KJ is lost to the surrounding air. The paddle wheel work amounts to 500 N- m. Determine the final energy of the system if its initial energy is 10 KJ

A. 35.5 KJ

A classroom that normally contain 40 people is to be air-conditioned with window air-conditioning units of 5 KW cooling capacity. A person at rest may be assumed to dissipate heat at a rate of about 360 Kj/hr. there are 10 light bulbs in the room, each with a rating of 100 watts. The rate of heat transfer to the classroom through the walls and the windows is estimated to be 15,000 Kj/hr. if the room air is to be maintained at a constant temperature of 21 degC, determine the number of window air-conditioning units required.

B. 2 units

4m X 5m x 6m room is to be heated by a baseboard resistance heater. It is desired that the resistance heater able to raise the air temperature in the room from 7 to 23 degC within 15 minutes. Assuming no heat losses from the room and an atmospheric pressure of 100 Kpa, determine the required power of the resistance heater. Assume constant specific heats at room temperature.

B. 1.91 KW

A student living in a 4m x 6m x 6m dormitory room turns on her 150 watts fan before she leaves the room on a summer day, hoping that the room will be cooled when she comes back in the evening, assuring all the doors and window are lightly closed and disregarding any heat transfer through the walls and the windows, determine a temperature in the room when she comes back 10 hours later. Use specific heat values at room temperature, and assume the room to be at 100 kpa and 15 degC in the morning when she leaves.

D. 58.13 degC

A piston-cylinder device whose piston is resting on top of a set of stops initially contains 0.50 kg of helium of gas at 100 Kpa and 25 degC. The mass of the piston is such that 500 KPa of pressure is required to raise it. How much heat must be transferred to the helium before the piston starts rising?

D. 1857.13 KJ

In order to cool 1 ton (1000 kg) of water at 20 degC in an insulated tank, a person pours 80 kg of ice at -5 degC into the water. Determine the final equilibrium temperature in the tank. The melting temperature and the heat of fusion of ice at atmospheric pressure are 0 degC and 333.7 KJ/kg, respectively.

A. 12.43 degC

A fan is powered by a 0.5 Hp motor and delivers air at a rate of 85 m^3/min. determine the highest value for the average velocity of air mobilized by the fan. Take the density of air to be 1.18 kg/m^3

B. 21.12 m/s

An ocean-thermal energy conversion power plant generates 10,000 KW using a water surface water inlet temperature of 28 degC and a cold deep-water temperature of 15 degC, on the basis of a 3 DegC drop in the temperature of the warm water and a 3 DegC rise in the temperature of the cold water due to removal and addition of heat. Calculate the power required in KW to pump the cold0deeo water to the surface and through the system heat exchanger if the required pumping pressure increase is 20 KPa. Assume a carnot cycle efficiency and density of cold water to be 1000 kg/m^3.

B. 250

A plate type solar energy collector with absorbing surface covered by a glass plate is to receive an inci… Radiation of 800 W/m^2. The glass plate has a reflectivity of 0.12 and a transitivity of 0.85. the absorbing surface has an absorptivity of 0.90. the area of the collector is 5 m^2. How much solar energy in watts is absorbed by the collector?

D. 3060

A tank contains liquid nitrogen at -120 degC is suspended in a vacuum shell by three stainless steel rods 0.80 meter and 3 meters long with a thermal conductivity of 16.3 W/m^2-C. if the ambient air outside the vacuum shell is 15 degC. Calculate the magnitude of the conductive heat flow in watts along the supports rods.

A. 0.168

An elastic sphere containing gas at 120 Kpa has a diameter of 1.0 m. heating the sphere causes it to expand its diameter of 1.3m, during the process the pressure is proportional to the sphere diameter. Calculate the work done by the gas in KJ.

C. 87.5

An ideal gas with a molecular weight of 7.1 kg/kg is compressed from 600 Kpa and 280 degK to a final specific volume of 0.5 m^3/kg. during the process the pressure varies according to p= 620 + 150v + 95 v^2 where p is in KPa and V in m^3/kg. calculate the work of compression in KJ/kg?

D. 33.33

A one cubic meter container contains a mixture of gases composed of 0.02 kg/mol of oxygen and 0.04 kg-mol helium at a pressure of 220 Kpa. What is the temperature of this ideal gas mixture in degrees kelvin?

A. 441

Methyl alcohol (CH3OH) is burned with 25% excess air. How much unburned oxygen in kg-mol- oxygen/kg-mol-fuel will there be in the products if the product of combustion is compete?

C. 0.37

A 12 DC electrical motor draws a current of 15 amps. How much work in KJ does this motor produce over a 10 minute period of operation?

A. 108.0

A 4 liter ( 2 liter per revolution at standard pressure temperature) spark engine has a compression ratio of 8 and 2200 KJ/kg Heat addition by the fluid combustion. Considering a cold air- standard Otto Cycle model, how much power will the engine produce when operating at 2500 rpm?

A. 166.53 HP

A simple Rankine produces 50 MW of power, 50 MW of process heated and rejects 50 MW of heat to the surroundings. What is the utilization factor of this cogeneration cycle neglecting the pump work?

C. 64%

The rate of heat transfer to the surroundings from a person at rest is about 400 Kj/Hr. suppose that the ventilation system falls in an auditorium containing 120 people and assuming that the energy goes into the air of volume 1500 m^3 initially at 300 degK and 101 Kpa , calculate the rate in degC/min of air temperature change.

C. 0.63

An insulated box containing helium gas falls from a balloon 4.5 Km above the __________. Calculate the temperature rise in degC of the helium when the box hits the ground.

D. 14.1

Consider two Carnot heat engines operating in series. The first engine receives heat from the reservoir at 2400 degK and rejects the waste heat to another reservoir at temperature T. the second engine receives heat from the first one, convert sine if it to work, and rejects the rest to a reservoir at 300 degK. If thermal efficiencies of both engines are the same, determine the temperature T.

A. 849 degK

An ideal gas mixture consist of 2 Kmol of N2 and 6 Kmol of CO2. The mass fraction of CO2 is:

C. 0.825

A carnot cycle is operates between the temperature limits of 300 degK and 1500 degK and produces 500 KW of net power. The value of entropy change of the working fluid during the heat addition process is,

C. 0.5 KW/k

Air in an ideal diesel cycle is compressed from 3 L to 0.15 L and then it expands during the constant pressure heat addition process to 0.3 L, under cold air standard conditions, the thermal efficiency of the cycle is

C. 65 percent

Air enters a turbojet engine at 200 m/s at a rate of 20 kg/s and exist at 800 m/s relative to the aircraft. The thrust developed by the engine is:

B. 12 KN

Heat engine receives heat from a source at 1200 DegK at a rate of 500 Kj/s and rejects the waste heat to a sink 300 degK. If the power output of the engine is 200 KW, the second law efficiency of this heat engine is

C. 53%

A water reservoir contains 100,000 kg of water at an average elevation of 60m. the maximum amount of electric power that can be generated from this water is:

B. 16 KWh

A house s maintained at 22 degC in winter by electric resistance heater. If the outdoor temperature is 5 degC, the second law efficiency of the resistance heater is:

B. 5.8 %

Thermoelectric refrigerator that resembles a small ice chest is powered by a car battery, and has a COP of 0.10. If the refrigerator cools a 0.350 L canned drink from 20 degC to 4 degC in 30 mins, determine the average electric power consumed bu the thermoelectric refrigerator.

A. 130 watts

Carnot refrigerator operates in a room in which the temperature is 25 degC and consumes 2KW of power when operating. If the food compartment of the refrigerator is to be maintained at 3 degC, determine the rate of heat removal from the food compartment.

A. 1504.8 KJ/min

A household refrigerator with EER 8.0 removes heat from the refrigerated space at a rate of 90 KJ/min. determine, the rate of heat transfer to the kitchen air

C. 128.46 Kj/min

An air conditioning system is used to maintain a house at 75 degF when the temperature outside is 95 degF. The house is gaining heat through the walls and windows at a rate of 1250 BTU/min, and the heat generation rate within the house from people, lights, and appliances amounts to 350 Btu/min. determine the minimum power input required for this air- conditioning system.

C. 1.41 HP

A refrigeration system is to cool bread loaves with an average mass of 450 g from 22 degC to -10 degC at a rate of 500 loaves per hour by refrigerated air. Taking the average specific and latent heats of the bread to be 2.93 Kj/kg – C and 109.3 KJ/Kg , respectively, determine the product load.

C. 761.5 KJ/min

A house that was heated by electric resistance heaters consumed 1200 KWh electric energy in a winter month. If this house were heated instead by a heat pump that has an average performance factor PF of 2.4, determine how much money the homeowner would be saved that month assume a price of 0.0855 $/KWh for electricity.

B. $59.5

An ammonia simple saturation cycle operates with a suction pressure of 291.6 Kpa and a condenser pressure of 1204 Kpa develops 15 Tons of refrigeration. Determine the theoretical horsepower of the compressor.

B. 13 HP

An ammonia ice plant operates between a condenser temperature of 35 degC and evaporator of -15 degC. It produces 10 metric tons of ice per day from water at 30 degC to ice at -5 degC. Assuming simple saturation cycle, determine the horsepower of the motor if the adiabatic efficiency of the compressor is 0.85 and mechanical efficiency is 0.95. the specific heat of ice is 2.094 Kj/Kg-C and the latent heat is 335 Kj/kg.

D. 21.9 HP

Freon 22 air conditioning under standard operating conditions of 35 degC condensing and 5 degC evaporating temperatures, the volume flow rate entering the compressor is 23.72 L/s. determine the refrigerating capacity if the refrigerating effect is 164 Kj/Kg.

D. 27.4 TR

The refrigerant volume flow rate at the entrance of compressor were obtained from a test on a twin cylinder, single acting 15 cm x 20 cm, 320 rpm compressor ammonia refrigerating plant to be 33 L/s. determine the volumetric efficiency of the compressor.

B. 87.6 %

100

Twin cylinder ammonia compressor with volume displacement of 14,726 cm^3 operates at 300 rpm. Condenser and evaporator pressure re 1200 Kpa and 227 Kpa respectively. Specific volume of refrigerant at the entrance of compressor is 528.26 kj/kg. compression process is polytropic with n = 1.20 and clearance factor of compressor is 2 percent. Determine horsepower required.

C. 80 HP

Machine Design ( 1st Set )

Jacky Shane Luyas Buhia · 20問 · 2年前

Machine Design ( 1st Set )