МЕСН 2344 QUIZ 3 Buring steady-state operation, a gearbox receives 60 kw through the input shaft and delivers power through the output shaft as shown in Figure 1. For the gearbox as the system, the rate of energy transfer by convection is Q = -hA(T, – T) where h = 0.171 kW/m² · K is the heat transfer coefficient, A =1.0 m² is the outer surface area of the gearbox, T = 300 K is the temperature at the outer surface, and T; = 293 K is the temperature of the surrounding air away from the immediate vicinity of the gearbox. For the gearbox, evaluate the heat transfer rate and the power delivered through the output shaft, each in kw T;= 203 K Input shaft Gearbox Output shaft Outer sarface A= 10 m Figure 1

МЕСН 2344 QUIZ 3 Buring steady-state operation, a gearbox receives 60 kw through the input shaft and delivers power through the output shaft as shown in Figure 1. For the gearbox as the system, the rate of energy transfer by convection is Q = -hA(T, – T) where h = 0.171 kW/m² · K is the heat transfer coefficient, A =1.0 m² is the outer surface area of the gearbox, T = 300 K is the temperature at the outer surface, and T; = 293 K is the temperature of the surrounding air away from the immediate vicinity of the gearbox. For the gearbox, evaluate the heat transfer rate and the power delivered through the output shaft, each in kw T;= 203 K Input shaft Gearbox Output shaft Outer sarface A= 10 m Figure 1

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter7: Forced Convection Inside Tubes And Ducts

Section: Chapter Questions

Problem 7.1DP

See similar textbooks

Similar questions

An ice plant produces 10 tons of ice per day at 0°C using water at room temperature of 33°C. Estimate the power rating (Electrical Power consumed by the motor to run compressor) of the compressor-motor, if the C.O.P. of the plant is 3.0 and overall electro-mechanical efficiency (η) is 91%. Note: Latent heat of ice is 335 kJ/kg, Cp = 4.18 kJ/kg.K.
Goal Solve for the performance coefficient of a refrigerator using a five-step process the includes:1. Making a state table.2. Making a process table.3. Calculating the totals for Work, Heat, and Internal-Energy-Change.4. Identifying the heat input (cold reservoir) and output (hot reservoir).5. Calculating the performance coefficient of the refrigerator.Problem Shown in the figure to the right is a cyclic process undergone by a refrigerator. Your refrigerator shall use 5.0 moles of helium gas (monatomic). During the process a->b, the volume increases by a factor of 3.0. Solution- (1) Fill in the State Table (all pressures in Pascals, all volumes in cubic meters, all temperatures in K). Pressure Volume Temperature a b c (2) Fill in the Process Table (all entries in Joules). Work Heat dU a->b b->c c->a (3) Find the Totals: Work = J Heat = J dU = J (4) Find the heat input (from "cold…
In a cyclic comprising of air compressor and expansion, workdone by a prism during the compression stroke is 9.2KJ and the heat rejected to the surrounding is 50KJ. During the expansion stroke workdone by air on the prism is 8.4KJ. a) Determine the quality of heat transferred to or from the system. Tullow oil has discovered a large volume of crude deposit at Cape-3-Point along the western coast of Ghana after years of intensive exploration. In the Company’s bid to start exploration, Green Ghana an environmental protection NGO took Tullow to court to prevent the Company from embarking on the said project citing numerous environmental concerns. b) As an energy and sustainability expert, what do you think are the side effects of the project and their remedies? A cooling water pump is operating at a speed of 1800rpm. Its flow rate is 1800L/minutes at a head of 14.4m and the power of the pump is 45kw. c) Determine the power required if the pump speed is increased…
The winter air conditioning system has a preheat coil, an air washer, and a reheat coil as processing units. It supplies air at 38°C db-temperature to a space maintained at 21°C db-temperature and 13°C wb-temperature. The sensible and latent heat loads on the space are 50 kW and 25 kW, respectively. Of the return air from the space, 40% by dry air mass is discharged to the ambient and replaced with fresh outdoor air at 2°C db-temperature and 95% relative humidity. In the preheater, the air is heated to a db-temperature of 21°C. Assume that the water added in the air washer is at the wb-temperature of the air entering it. The pressure is constant at 95 kPa. Determine:The mass flow rate of supply air in kg/s.The rate of heat input in the preheat coil in kW.The mass flow rate of water sprayed in the air washer in kg/s.
1. A heat exchanger is located on the roof of a warehouse to heat the air in winter. It is a coil-shaped pipe into which water vapor enters at 0.1 MPa and 300 °C and leaves with a quality of 30%. The warehouse has the following dimensions: 80m x 160m x 10m. The air must be heated from 5°C to 22°C. a. What must be the mass flow rate of the water to heat the air in less than half an hour? b. We want to cool the steam from the exchanger outlet and bring it up to 50 °C. For this, a mixing chamber with water at 20 °C is used, what will be the proportion of the steam mixture? c. The exchanger is damaged and only liquid water can be used at the same pressure (inlet T. 1 °C below saturation and outlet T. at 30°C). How long does it take to heat the air with the same flow of water?
In an absorption refrigerator, the energy driving the process is sllPplied not as work, but as heat from a gas flame. (Such refrigerators commonly use propane as fuel, and are used in locations where electricity is unavailable. *) Let us define the following symbols, all taken to be positive by definition: Qf = heat input from flame Qe = heat extracted from inside refrigerator Qr = waste heat expelled to room Tf = temperature of flame Te temperature inside refrigerator Tr = room temperature Explain why the "coefficient of performance" (COP) for an absorption refrigerator should be defined as Qc/Qf.
An air conditioning unit works by taking heat out of a room. As the refrigerant gas expands in the cooling coils, it absorbs heat from the circulating air in the room. This heat is then released as the refrigerant is compressed by the part of the unit that is directed out of the room. The unit serves like a heat pump for the room. Since a refrigerator works in a similar manner, can t also be used to maintain a cool temperature inside a room? Justify your answer.
Diesel Cycle:16. A Diesel Cycle has a volume displacement of 0.95 m3 and the volume at during heat rejection is 1 m3. Determine the volume at the end of heat addition if the cut-off ratio 2.25.
In an absorption refrigerator, the energy driving the process is sllPplied not as work, but as heat from a gas flame. (Such refrigerators commonly use propane as fuel, and are used in locations where electricity is unavailable. *) Let us define the following symbols, all taken to be positive by definition: Qf = heat input from flame Qe = heat extracted from inside refrigerator Qr = waste heat expelled to room Tf = temperature of flame Te temperature inside refrigerator Tr = room temperature Use the second law of thermodynamics to derive an upper limit on the COP, in terms of the temperatures Tf, Te, and Tr alone.
Half of the power produced by a Carnot engine is used to operate a Carnot heat pump, which must maintain the interior of a house at 22 ° C, when the ambient temperature is 2 ° C and it is estimated that the house it has heat losses of 62,000 kJ / h. The motor is known to operate between the temperature limits of 800 ° C and 20 ° C. Determine: a) The power required to operate the heat pump b) The heat flux supplied to the motor c) The coefficient of operation of the heat pump d) The efficiency of the motor
The ice maker inside a refrigerator makes ice cubes at 0.0°C from water that is at 17.2°C when it first enters the ice maker. If this machine is rated at 184 W and has a 2.96 coefficient of performance, what is the maximum amount of ice it can produce in a 24 hour period without any interruption or stoppage? Assume that the ice maker works just like a refrigerator. The specific heat of water is 4184 J/(kg · °C), and the latent heat of fusion of ice is 33.4 ✕ 104 J/kg.
The heat transfer rate from a refrigerator consuming 9 kJ of electrical energy per minute to the room environment is 400 W. In this case:a) The heat extraction rate from the internal environment of the refrigerator (kJ/s),b) Calculate the performance coefficient of the refrigerator.