Consider the composite wall below. The inner side of the wall is subjected to air flow at 430°C with a heat transfer coefficient of 25 W/m² C and the outter side is subjected to air flow at 55°C with heat transfer coefficient of 10 W/m²-C. If KA = 150 W/m-C, KB = 30 W/m-C, Kc = 65 W/m-C, and Kp = 50 W/m-C, and assuming one dimensional heat flow. Find the rate of heat transfer across the wall.

Consider the composite wall below. The inner side of the wall is subjected to air flow at 430°C with a heat transfer coefficient of 25 W/m² C and the outter side is subjected to air flow at 55°C with heat transfer coefficient of 10 W/m²-C. If KA = 150 W/m-C, KB = 30 W/m-C, Kc = 65 W/m-C, and Kp = 50 W/m-C, and assuming one dimensional heat flow. Find the rate of heat transfer across the wall.

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.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.19P: 1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the...

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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.
1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the convection heat transfer coefficient between the outer surface of the container and the air is 6.8 , the temperature of the air is 27°C, and the temperature of the surface of the sphere is –183°C, determine the rate of heat transfer by convection.
1.60 Two electric resistance heaters with a 20 cm length and a 2 cm diameter are inserted into a well-insulated 40-L tank of water that is initially at 300 K. If each heater dissipates 500 W, what is the time required for bringing the water temperature in the tank to 340 K? State your assumption for your analysis.
A cooling system is to be designed for a food storage warehouse for keeping perishable foods cool prior to transportation to grocery stores. The warehouse has an effective surface area of 1860 m2 exposed to an ambient air temperature of 32C. The warehouse wall insulation (k=0.17W/(mK)) is 7.5 cm thick. Determine the rate at which heat must be removed (W) from the warehouse to maintain the food at 4C.
2. You drive a car on a winter day with the atmospheric air at-10°C, and you keep the outside front windshield surface temperature at +3 °C by blowing hot air on the inside surface. If the windshield is 0.7 m and the outside convection coefficient is 210 W/m² K, find the rate of energy loss through the front windshield. For that heat transfer rate and a 0.25-inch-thick glass with k = 1.40 W/m K, what is the inside windshield surface temperature"
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In a thermal power plant, a horizontal copper pipe of "D" diameter, "L" length and thickness 1.7 cm enters into the boiler that has the thermal conductivity as 0.3 W/mK. The boiler is maintained at 107degreeC and temperature of the water that flows inside the pipe is at 31degreeC. If the energy transfer (Q) is 124925 kJ in 7 hours. Determine the Heat transfer rate, Surface area of the pipe and Diameter & Length of the pipe, if D = 0.012 L.Change in Temperature (in K) Heat Transfer Rate (in W) Surface Area of the Pipe (m2) Pipe Length (in m) Pipe Diameter (in mm)
QUESTION 3: Warm air is blown over the inner surface of the windshield of an automobile to defrost ice accumulated on the outer surface. The windshield has a thickness of 5 mm and thermal conductivity of 1.4 W/m-K. The outside ambient temperature is -10°C and the convection heat transfer coefficient is 200 W/m²-K, while the ambient temperature inside the automobile is 25°C. Determine the value of the convection heat transfer coefficient for the warm air blowing over the inner surface of the windshield necessary to cause the accumulated ice to begin melting.
A Spherical Container Is Made Of Plastic (K=2 W/MK, Ρ=5000 Kg/M) And Has Inner And Outer Radii Of 10 Cm And 11 Cm, Respectively. Hot Oil (C=3000 J/KgK, Ρ=800 Kg/M3) At 80 0C Is Stored Within The Container And The Heat Transfer Coefficient Between The Oil And The Inner Surface Of The Container H=30W/M2K The Outer Surface Of The Container IsThis problem has been solved! See the answerA spherical container is made of plastic (k=2 W/mK, ρ=5000 kg/m) and has inner and outer radii of 10 cm and 11 cm, respectively. Hot oil (c=3000 J/kgK, ρ=800 kg/m3) at 80 0C is stored within the container and the heat transfer coefficient between the oil and the inner surface of the container h=30W/m2K The outer surface of the container is perfectly insulated. Solve the differential equation under the boundary conditions for steady one dimensional heat conduction through the plastic material. a)obtain an equation fort he variation of temperature within the plastic material? b) Calculate the temperature of…
A cold storage wall, whose components and dimensions are given below, is formed by connecting layers A, B, C, D, E and F in series and in parallel. The temperature of the outside air is 30 oC and the temperature of the inside of the warehouse is -4 oC. If the film heat transfer coefficient between the air in the warehouse and the E layer is 24 W/m2 oC and the film heat transfer coefficient between the outer surface of the flat wall (A and F layers surface) and the atmospheric air is 16 W/m2 oC; Calculate the heat transferred in a day. (KA= 0.17 W/m.K, kc 0.98 W/m.K) (kD= 0.21 W/m.K, KF= 0.58 W/m.K) XA=3cm B KBK= 0.024 W/m.K, KE=0.01 W/m.K, F C D E XB=14 cm Xc=Xp=8cm XE=10cm AF AC AD= A/3 h= 2 m 70 cm
The thickness of one wall is 0.07 m. The right side of the wall is exposed to ambient air with a temperature of T = 310 K and Tsur= 300 K. If the external surface temperature of the wall (right side) is 500 K and the coefficient of heat transfer is h=30W/m²K, the rate of propagation is 0.78, and the coefficient of heat transmission of the wall is k=0.86 W/m²K, what is the temperature of the inner wall?
Consider a large plane wall of thickness L = 0.4 m, thermal conductivity k=2.3 W/m °C,and surface area A= 20 m2. The left side of the wall at x= 0 is subjected of T1 = 80 C. while the right side losses heated by convection to the surrounding air at Too=15 C with a heat transfer coefficient of h=24 W/m2 .C. Assuming constant thermal conductivity and no heat generation in the wall, (a) express the differential equation and the boundary conditions for steady one-dimensional heat conduction through the wall, (b) obtain a relation for the variation of temperature in the wall by solving the differential equation, and (c) evaluate the rate of heat transfer through the wall