The piston cylinder of a motorcycle engine is constructed of AISI 316 stainless steel, having a height H = 0.22 m and an outside diameter D = 45 mm. Under typical operating conditions, the outer surface of the cylinder is at a temperature of 600 K and is exposed to ambient air at 250 K, with a convective coefficient of 62 W/(m2-K). Annular fins are integrally fused with the cylinder to increase heat transfer to the surroundings. Consider five of these fins, with thickness t = 6 mm, length L = 20 mm and equally spaced. What is the increase in heat transfer rate due to the use of fins?

The piston cylinder of a motorcycle engine is constructed of AISI 316 stainless steel, having a height H = 0.22 m and an outside diameter D = 45 mm. Under typical operating conditions, the outer surface of the cylinder is at a temperature of 600 K and is exposed to ambient air at 250 K, with a convective coefficient of 62 W/(m2-K). Annular fins are integrally fused with the cylinder to increase heat transfer to the surroundings. Consider five of these fins, with thickness t = 6 mm, length L = 20 mm and equally spaced. What is the increase in heat transfer rate due to the use of fins?

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 3.10P: 3.10 A spherical shell satellite (3-m-OD, 1.25-cm-thick stainless steel walls) re-enters the...

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3.10 A spherical shell satellite (3-m-OD, 1.25-cm-thick stainless steel walls) re-enters the atmosphere from outer space. If its original temperature is 38°C, the effective average temperature of the atmosphere is 1093°C, and the effective heat transfer coefficient is , estimate the temperature of the shell after reentry, assuming the time of reentry is 10 min and the interior of the shell is evacuated.
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.
based on the information given here. 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 with the space between the fins 4-mm. The efficiency of these fins is 0.97 and the surface area of a single fin is 0.001916 m2. Heat is transferred to the surrounding air at 25°C, with a heat transfer coefficient of 40-W/m2°C. The total heat transfer from the finned tube per meter length in W is approximately 1910 3080 cannot be determined 2495
based on the information given here. 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 with the space between the fins 4-mm. The efficiency of these fins is 0.97 and the surface area of a single fin is 0.001916 m2. Heat is transferred to the surrounding air at 25°C, with a heat transfer coefficient of 40-W/m2°C. The surface effectiveness for the finned surface is approximately O 2.56 3.16 1.97 cannot be determined
based on the information given here. 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 with the space between the fins 4-mm. The efficiency of these fins is 0.97 and the surface area of a single fin is 0.001916 m2. Heat is transferred to the surrounding air at 25°C, with a heat transfer coefficient of 40-W/M2°C. The increase in heat transfer from the tube per meter length in W is approximately 936 2105 1521 cannot be determined
Troom = 25°C Problem-4: An 8-m-internal-diameter spherical tank made of 1.5-cm-thick stainless steel (k = 15 W/m-K) is used to store iced water at 0°C. The tank is located in a room whose temperature is 25°C. The walls of the room are also at 25°C. The outer surface of the tank is black (emissivity = 1), and heat transfer between the outer surface of the tank and the surroundings is by natural convection and radiation. The convection heat transfer coefficients at the inner and the outer surfaces of the tank are 80 W/m²-K and 10 W/m².K, respectively. Determine (a) the rate of heat transfer to the iced water in the tank and (b) the amount of ice at 0°C that melts during a 24-h period. The heat of the fusion of water at atmospheric pressure is hf5 333.7 kJ/kg. Iced water D D₁= 8 m Tin = 0°C 1.5 cm
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Heat transfer
Water flows at 50°C inside a 2.5-cm-inside-diameter tube such that h, =3500 W/m²'C. The tube has a wall thickness of 0.8 mm with a thermal conductivity of 16 W/m C. The outside of the tube loses heat by free convection with h. =7.6W/m²C. Calculate the overall heat-transfer coefficient and heat loss per unit length to surrounding air at 20 C.
The rectangular wall of a furnace consists of 3in. fire clay brick surrounded by 0.25in. of steel on the outside. There are six 0.25in.diameter mild steel bolts per square foot connecting the steel and the brick. The furnace is surrounded by 70°F air (with a film coefficient of 1.65 Btu/hr-ft²-°F), while the inner surface of the brick is maintained at a constant 1000°F. Determine the heat flux per square foot through this wall?
A sphere of 80 mm diameter (k=50 W/m.K and α=1.5x10-6 m2/s) is initially at a uniform, elevated temperature, and is quenched in an oil bath maintained at 30 °C. The convection coefficient for the cooling process is 1100 W/m2K. At a certain time, the surface temperature of the sphere is measured to be 120 °C. What is the corresponding center temperature of the sphere?
A total of 10 rectangular aluminum fins (k = 203 W/m-K) are placed on the outside flat surface of an electronic device. Each fin is 100 mm wide, 20 mm high and 4 mm thick. The fins are located parallel to each other at a center-to center distance of 8 mm. The temperature at the outside surface of the electronic device is 60°C. The air is at 20°C, and the heat transfer coefficient is 100 W/m? ‘K. Determine (a) the rate of heat loss from the electronic device to the surrounding air and (b) the fin effectiveness.