An insulated steam pipe (k = 312 Btu-in/hr.ft2.0F), located where the ambient temperature is 90 deg F, has an internal diameter of 2 in and external diameter of 2.25 in. The outside diameter of the corrugated asbestos insulation (k = 0.828 Btu-in/hr.ft2.0F) is 5 in and the surface coefficient on the outside is 2.5 Btu/hr.ft2.0F. On the inside, the steam has a temperature of 300 deg F and h = 1000 Btu/hr.ft2.0F. Compute (a) the heat loss per foot of the pipe length, and (b) the surface temperature on the inside of the insulation.

An insulated steam pipe (k = 312 Btu-in/hr.ft2.0F), located where the ambient temperature is 90 deg F, has an internal diameter of 2 in and external diameter of 2.25 in. The outside diameter of the corrugated asbestos insulation (k = 0.828 Btu-in/hr.ft2.0F) is 5 in and the surface coefficient on the outside is 2.5 Btu/hr.ft2.0F. On the inside, the steam has a temperature of 300 deg F and h = 1000 Btu/hr.ft2.0F. Compute (a) the heat loss per foot of the pipe length, and (b) the surface temperature on the inside of the insulation.

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.

Chapter3: Transient Heat Conduction

Section: Chapter Questions

Problem 3.16P: 3.16 A large, 2.54-cm.-thick copper plate is placed between two air streams. The heat transfer...

See similar textbooks

Similar questions

2.38 The addition of aluminum fins has been suggested to increase the rate of heat dissipation from one side of an electronic device 1 m wide and 1 m tall. The fins are to be rectangular in cross section, 2.5 cm long and 0.25 cm thick, as shown in the figure. There are to be 100 fins per meter. The convection heat transfer coefficient, both for the wall and the fins, is estimated to be K. With this information determine the percent increase in the rate of heat transfer of the finned wall compared to the bare wall.
A plane wall, 7.5 cm thick, generates heat internally at the rate of 105 W/m3. One side of the wall is insulated, and the other side is exposed to an environment at 90C. The convection heat transfer coefficient between the wall and the environment is 500 W/m2 K. If the thermal conductivity of the wall is 12 W/m K, calculate the maximum temperature in the wall.
3.16 A large, 2.54-cm.-thick copper plate is placed between two air streams. The heat transfer coefficient on one side is and on the other side is . If the temperature of both streams is suddenly changed from 38°C to 93°C, determine how long it takes for the copper plate to reach a temperature of 82°C.
1.10 A heat flux meter at the outer (cold) wall of a concrete building indicates that the heat loss through a wall of 10-cm thickness is . If a thermocouple at the inner surface of the wall indicates a temperature of 22°C while another at the outer surface shows 6°C, calculate the thermal conductivity of the concrete and compare your result with the value in Appendix 2, Table 11.
Steam at T1 = 320°C and h1 = 60 W/m2·°C flows in a cast iron pipe (k = 80 W/m·°C). The inner and outer diameters are D1 = 5 cm and D2 = 5.5 cm, respectively. The insulation thickness is 3-cm-glass wool insulation with k= 0.05 W/m · °C. The temp. of the surroundings at T2 = 5°C and heat transfer coefficient of h2=18 W/m2·°C. Determine 1. Heat loss from the steam per unit length of the pipe. 2. Determine the temperature at the surfaces of the pipe and the insulation.
A steel duct whose internal diameter is 5.0 cm, and external diameter is 7.6 cm and thermal conductivity is: k = 15.0 (W/(m ºC)) is covered with an insulating material whose thickness is 2.0 cm and of thermal conductivity k = 0.2 (W/(m ºC)). A hot gas flows through the interior of the duct at a temperature of 330.0 ºC that generates a heat transfer coefficient by forced convection h=400.0 (W/(m^2 · ºC)). The outer surface of the insulating layer is exposed to air whose temperature is 30.0 ºC with forced convection heat transfer surface h = 60.0 (W/(m^2 · °C)). As a process engineer and in charge of company operations, you have been asked to: i. Determine the heat loss experienced by the pipe along 10.0 m.ii. The temperature drops that are generated in the different thermal resistances of the system. That is, on the air side, the duct wall and on the hot gas side.
The exterior wall of a building consists of 100 mm thick face brick (k = 0.9 W/m∙K), 40 mm thick polystyrene insulating board (k = 0.036 W/m∙K), 125 mm thick concrete block (k = 1.8 W/m∙K) and 15 mm thick interior gypsum board (k = 0.18 W/m∙K). The inside and outside convective heat transfer coefficients are 6.5 W/m2∙K and 22.5 W/m2∙K, respectively. The outside air temperature is -5°C and the inside air temperature is 20°C. The wall is 3 m high and 15 m long. Calculate the rate of heat loss (in W) through the wall.
A domestic refrigerator with inner dimensions of 0.7 m by 0.7 m at the base and height 1 m was designed to maintain a set temperature of 6 ˚C. The bodies consist of two 10-mm-thick layers of Aluminium (k = 225 W/mK) separated by a 30 mm polyurethane insulation (k=0.028 W/mK). If the average convection heat transfer coefficient at the inner and outer surfaces are 11.6 W/m2K and 14.5 W/m2K respectively, calculate: Data: Hgt = , W = , L1 = L3 = = m, k1= k3 = , L2 = = , k2 = , T∞1 = , T∞2 = , ho= , hi = .
The exterior wall of a building consists of 120 mm thick face brick (k = 0.9 W/m∙K), 45 mm thick polystyrene insulating board (k = 0.036 W/m∙K), 152 mm thick concrete block (k = 1.8 W/m∙K) and 16 mm thick interior gypsum board (k = 0.18 W/m∙K). The inside and outside convective heat transfer coefficients are 6.5 W/m2∙K and 22.5 W/m2∙K, respectively. The outside air temperature is -5°C and the inside air temperature is 21°C. The wall is 3 m high and 16 m long. Calculate the rate of heat loss (in W) through the wall. calculate the temperature (in °C) of the interior surface of the wall. calculate the temperature (in °C) of the exterior surface of the wall.
Question 1: The exterior wall of a building consists of 100 mm thick face brick (k = 0.9 W/m∙K), 40 mm thick polystyrene insulating board (k = 0.036 W/m∙K), 125 mm thick concrete block (k = 1.8 W/m∙K) and 15 mm thick interior gypsum board (k = 0.18 W/m∙K). The inside and outside convective heat transfer coefficients are 6.5 W/m2∙K and 22.5 W/m2∙K, respectively. The outside air temperature is -5°C and the inside air temperature is 20°C. The wall is 3 m high and 15 m long. Calculate the rate of heat loss (in W) through the wall. Follow-up question to Question 1, calculate the temperature (in °C) of the interior surface of the wall. Follow-up question to Question 1, calculate the temperature (in °C) of the exterior surface of the wall. Note: Round the answers to 2 decimal places.
a pipe with an outside diameter of 2.5 inches is insulated with 2 inches layer of asbestos ( K= 0.396(btu-in)/(hr-ft-F) followed by a layer of cork 1.5 inches thick ( K= 0.30 (btu-in)/ft (hr-ft-F). if the temperature of the outer surface of the cork and pipe is 90 F and 290 F RESPECTIVELY, calculate the heat loss per 100 ft of insulated pipe in btu/hr
It is desired to keep the interior of a refrigerator at 2 °C whose dimensions at the base are 0.8 x 0.8 m and the height is 1.9 m. The walls of the refrigerator are made of two sheets of steel, 0.28 cm thick with 3 cm of fiberglass insulation. The interior and exterior coefficients are, respectively, 10 W/m^2 °C and 15 W/m^2 °C. If the ambient temperature in the kitchen is 30°C, estimate the heat flux that must be extracted to maintain the specified conditions. Make a proposal to prevent heat from entering the refrigerator.