Steam in a heating system flows through tubes whose outer diameter is 5 cm and whose walls are maintained at a temperature of 180°C. Circular aluminum alloy 2024-T6 fins (k = 186 W/m · °C) of outer diameter 6 cm and constant thickness 1 mm are attached to the tube. The space between the fins is 3 mm, and thus there are 250 fins per meter length of the tube. Heat is transferred to the surrounding air at T= 25°C, with a heat transfer coefficient of 40 W/m? · °C. Determine the increase in heat transfer from the tube per meter of its length as a result of adding fins.

Steam in a heating system flows through tubes whose outer diameter is 5 cm and whose walls are maintained at a temperature of 180°C. Circular aluminum alloy 2024-T6 fins (k = 186 W/m · °C) of outer diameter 6 cm and constant thickness 1 mm are attached to the tube. The space between the fins is 3 mm, and thus there are 250 fins per meter length of the tube. Heat is transferred to the surrounding air at T= 25°C, with a heat transfer coefficient of 40 W/m? · °C. Determine the increase in heat transfer from the tube per meter of its length as a result of adding fins.

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

Steam passes into tubes in a heating system whose outer diameter is 3 cm and whose wall is held at a temperature of 120°C. Tubes are connected to circular aluminium alloy fins (k = 180 W/m. ° C) with an outer diameter of 6 cm and a constant thickness of 2 mm. The distance between the two fins is 3 mm and the tube length is 200 fins per meter. With h = 60 W/m2.°C, the heat is transmitted to the ambient air at 25°C. Evaluate the increase in heat transfer from the tube per meter of its length as a result of adding fins.
Example 2: The roof of an electrically heated home is 6 m long, 8 m wide, and 0.25 m thick, and is made of a flat layer of concrete whose thermal conductivity is k=0.8 W/m·°C. The temperatures of the inner and the outer surfaces of the roof one night are measured to be 15°C and 4°C, respectively, for a period of 10 hours. Determine the rate of heat loss through the roof that night
An insulation covers a spherical vessel whose diameter is 1 meter. The insulation has a k value of 17 W/m · °C, and the surface convective coefficient is 6 W/m2. Find the thickness of the insulation if the surrounding air is at 25 oC and the total heat loss shall not exceed 500 W.
Brass plate of 6 cm thickness that are initially at 25 °C are heated by passing it through an oven that is maintained at 700 •C. The plate remains in the oven for a period of 10 minutes. Taking the heat transfer coefficient (h= 130 W/m2. °C). Determine the center temperature of the plate and the temperature at the distance of 2 cm from the center of the plate. Taking p=8530 kg/m3, Cp=380 J/kg. • * .C, a= 33.9*10-6 m2/s
A camper has a propane-powered refrigerator. The refrigerator consumes approximately 0.50 kgof propane per day. When propane is burned completely, it releases approximately 50. MJ/kg.The interior of the refrigerator is maintained at an average temperature of 2.0 °C, and theexterior temperature is 22 °C. Assume that the refrigerator has a surface area of 2.0 m2 and thatthe insulation has an R-value of 3.2 K · m2/W.(a) At what rate does heat flow into the refrigerator?(b) At what rate must the refrigerator remove heat from its interior?(c) How much energy is released per second from the propane combustion?(d) How much heat is delivered to the room?
Most automobiles have a coolant reservoir to catch radiator fluid that may overflow when the engine is hot. Such a radiator, made of copper, is filled to its 12-L capacity when at 10.0°C. -What volume of radiator fluid, in liters, will overflow when the radiator and fluid reach their 99.5°C operating temperature, given that the fluid’s thermal coefficient of volume expansion is 400.0 × 10-6 / °C? The coefficient of volume expansion for copper is 5.1 × 10-5 /°C.
The wall of a furnace has an inner temperature of 500 F. The wall has a thickness of 2 inches and has a thermal conductivity of 0.02 Btu/(h·ft·F). On the outside, air at 30 F flows over the 10 ft x 10 ft wall at a speed of 10 ft/s. Determine the rate of heat loss from the furnace to the environment. Use thermal resistance to solve
The temperature at the inner and outer surfaces of a boiler wall made of 20 mm thick steel and covered with an insulating material of 5 mm thickness are 300° C and 50° C respectively. If the thermal conductivities of steel and insulating material are 58W/m'C and 0.116 W/m'C respectively, determine the rate of flow through the boiler
The temperature of a gas stream is to be measured by a thermocouple whose junction can be approximated as a 1.2-mm-diameter sphere. The properties of the junction are k = 35 W/m °C, ρ= 8500 kg/m3 ,and Cp = 320 J/kg °C, and the heat transfer coefficient between the junction and the gas is h = 65 W/m2 °C. Determine how long it will take for the thermocouple to read %95 of the initial temperature difference.
A bare fuel rod has a diameter of 0.373 in and length of 12 ft. The volumetric heat generation rate for this rod is q′′′ = 10,000 kW/ft3. The heat produced by the rod is removed by water used as the coolant, at 2250 psia and 575 F. Find the heat transfer coefficient between the bare fuel rod and the coolant.The fuel rod surface temperature is 675 F
6. 1 - J: Water is passed through a 3 cm internal diameter, 8 m long tube is heated from 15 °C to 75°C . The tube is equipped with an electric resistance heater, which provides uniform heating throughout the surface of the tube. The outer surface of the heater is well insulated, so that in steady operation all the heat generated in the heater is transferred to the water in the tube. If the system is to provide hot water at a rate of 8 L/min, determine the power rating of the resistance heater. Also, estimate the inner surface temperature of the pipe at the exit. L 3 p= 990.1kg/m? k = 0.637 W/m.°C v = u/p=0.602 x10-6 m²/s C, = 4180 J/kg.°C Pr = 3.91
In a furnace, the inner and outer sides of the brick wall (k1 = 2.5W/mK) are maintained at 1100°C and 700°C respectively as shown in figure. 1100°C 700°C 200°C Heat flux= 2500 Ww/m2 Brick wall k=2.5 W/m.K Insulation, k2 L2 = L1/4 The brick wall is covered by an insulating material of thermal conductivity k2. The thickness of the insulation is 1/4h of the thickness of the brick wall. The outer surface of the insulation is at 200°C. The heat flux through the composite walls is 2500 W /m?. The value of k2 is. W/mK (round off to 2 decimal places).