Lux through a particular zone in a cast iron liner 1 em thick is erage coolant temperature is 85 ...
The temperature distribution across a wall 0.2 m thick at a certain instant of time is T(x) = a + bx + cxº, where T is in degrees Celsius and x is in meters, a = 200°C, b = -190°c/m, and c = 30°C/m2. The wall has a thermal conductivity of 1 W/m.k. (a) On a unit surface area basis, determine the rate of heat transfer into and out of the wall and the rate of change of energy stored...
Steam at T = 300C flows in a cast iron pipe shell with thermal conductivity k1=80W/mC, inner and outer diameter D1 = 5cm, and D2 =6cm respectively, and length L = 1m (notice that the cast iron pipe shell is a zone of conduction physically realized by the space between two concentric cylinders). The heat transfer coefficient for the steam inside the pipe is h1 = 60 W/m2. Furthermore, heat is lost to the surroundings at T2 = 5C through...
[6] A 20-cm thick wall of a house made of brick (k = 0.72W/m. C) is subjected to inside air at 22.C with a convection heat-transfer coefficient of 15 W/m2. C. The inner surface temperature of the wall is 18 C and the outside air temperature is -1 °C. Determine the outer surface temperature of the wall and the heat-transfer coefficient at the outer surface.
A 5-cm-diameter shaft rotates at 4500 rpm in a 15-cm long, 8-cm-outer-diameter cast iron bearing (k =70 W/m.K) with a uniform clearance of 0.6 mm filled wwith tubricating oil (u 0.03 N.s/m2 and k 0.14 W/m.K). The bearing is cooled externally by a liquid, and its outer surface is maintained at 40°C. Disregarding heat conduction through the shaft and assuming one- dimensional heat transfer, determine (a) the rate of heat transfer to the coolant, (b) the sutacs temperature of the...
A hot fluid passes through a thin-walled tube of 10-mm diameter at 18 kg/h at a temperature of 85 C. On the outside, coolant flows across the tube at a velocity of 3 m/s at a temperature of 25 C. Neglecting the thermal resistance of the metal wall, calculate 1. (a) The two heat transfer coefficients, (b) Overall heat transfer coefficient, and (c) Cooling rate (in W/m) achieved in the given configuration Assume hot fluid properties are constant at the...
Problem 3 (30): Steam at Too,1 340 °C flows in a cast iron pipe [k- 80 W/m.°C] whose inner and outer diameter are Di 6 cm and D2 -8 cm, respectively. The pipe is covered with a 4-cm thick glass wool insulation [k-0.05 W/ m°C]. Heat is lost to the surroundings at Too,2 - 21°C by natural convection and radiation, with a combined heat transfer coefficient of h- 18 W/m2 °C. Taking the heat transfer coefficient inside the pipe to...
2.) A plane wall is made of brick with a thermal conductivity of 1.5 W/(m-K). The wall is 20 cm thick and has a surface area of 10 m2. One side of the wall is exposed to outside air blowing against the wall resulting in a heat transfer coefficient of 20 W/(m2-K). The other side is exposed to an air-conditioned room with a convective heat transfer coefficient of 5 W/(m2-K). a. What are the thermal resistances corresponding to conduction through...
The wall of a house is 3 m high, 10 m long and 30 cm thick; it has an effective thermal conductivity of 10 W/m K. The outer surface of the wall has an emissivity of 0.75. On a winter night, the outer surface of this wall is at a temperature of 0 °C and the air is at a temperature of –10 °C. The heat transfer coefficient for the outside wall is 8 W/m2 K. The outside wall also...
Heat transfer question. A large wall made of 10-cm-thick solid brick (k = 0.8 W/m.K, p 2000 kg/m3, and p 800 J/kg.K) is originally at a uniform temperature of 30°C. The wall is adiabatic (well insulated) on one side as shown in the figure. The other surface is suddenly exposed to convection air flow at 10°C, resulting in a heat transfer coefficient h=40W/m2.K. Fluid (4.1) Determine the temperature of both surfaces Gr 0 and x 10 cm) after 5 hr...
Question 11 (15 points) The wall of a liquid-to-gas heat exchanger has a surface area on the liquid side of 1.8 m2 (0.6 m * 3.0 m) with a heat transfer coefficient of 255 W/m2 K. On the other side of the heat exchanger wall a gas flows, and the wall has 96 thin rectangular steel fins 0.5 cm thick and 1.25 cm high (k = 3 W/m K) as shown in the figure below. The fins are 3 m...