A metal spherical tank is filled with chemicals undergoing an exothermic reaction. The reaction provides a uniform heat flux on the inner surface of the tank. The tank has an inner diameter of 5 m, and its wall thickness is 10 mm. The tank vall has a variable thermal conductivity given as
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Heat and Mass Transfer: Fundamentals and Applications
- • An aluminum pot contains water that is kept steadily boiling (100 °C). The bottom surface of the pot, which is 12 mm thick and 1.5x10t mm2 in area, is maintained at a temperature of 102°C by an electric heating unit. Find the rate at which heat is transferred through the bottom surface. Compare this with a copper based pot. Tc 0 0 L=12mm Base of pot TH A= area of basearrow_forwardA silicon wafer with thickness of 925 µm is being heated with a uniform heat flux at the lower surface. The silicon wafer has a thermal conductivity that varies with temperature and can be expressed as k(T) = (a + bT + cT2) W/m·K, where a = 450, b = -1.29, and c = 0.00111. To avoid warping, the temperature difference across the wafer thickness cannot exceed 2°C. If the upper surface of the silicon wafer is at a uniform temperature of 600 K, determine the maximum allowable heat flux. (Round your answer up to 2 decimal places.)arrow_forwardDetermine the ratio of thermal conductivity for N2 at sea level (T = 300 K, P = 1 atm) versusthe lower stratosphere (T = 230 K, P = 0.25 atm).arrow_forward
- Saved Help Save & Exit A 2-kW resistance heater wire with thermal conductivity of k= 70 W/m-K, a diameter of D= 4 mm, and a length of L = 0.9 m is used to boil water. If the outer surface temperature of the resistance wire is Ts= 230°C, determine the temperature at the center of the wire. (Round your answer to a single decimal place.) 230 C -D→ es Resistance heater The temperature at the center of the wire is °C 18°C Clear ^ 4 ENGarrow_forwardA coil-shaped cooling pipe is made of SS-304 material. This pipe is 1 ft long, 0.4 inch outside diameter, and inch inside diameter. This coil cooling pipe is used to cool the water in the bath. The temperature of the inner coil pipe is 40oF while the outer coil in contact with water is 80oF. The thermal conductivity of SS-304 is a function of temperature where k(T) = 7.75 + (7.78 x 10-3).T where k is in Btu/h.ft.oF and T is in oF. Calculate the rate of heat dissipation in watts! (1287.7)arrow_forwardA cylindrical rod of stainless steel is insulated on its exterior surface except for the ends. The steady-state temperature distribution is T(x) = a - bx/L, where a = 305 K and b = 11 K. The diameter and length of the rod are D = 20 mm and L= 100 mm, respectively. Determine the heat flux along the rod, qx, in W/m2. Hint: The mass of the rod is m = 0.2480 kg. q" = 1639 W/m² Attempts: 1 of 1 usedarrow_forward
- 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 Farrow_forwardH.W. Q: An aluminum pan whose thermal conductivity is 237 W/m-°C has a flat bottom with diameter 20 cm and thickness 0.4 cm. Heat is transferred steadily to boiling water in the pan through its bottom at a rate of 800 W. If the inner surface of the bottom of the pan is at 105°C, determine the temperature of the outer surface of the bottom of the pan. 105°C 0.4 cm Answer: T= 105.43 °C 800 W 7arrow_forwardqo =4x10' W/m³ heat is produced in a radioactive material with a spherical shape with a diameter of R = 0.2 meters. The heat produced is released from the spherical surface to the environment with a stable regime. Thus, the temperature on the surface is kept constant at T=800C. The heat conduction coefficient of the object is given as k=15W/mC The temperature of the spherical body changes only in the radial direction. temperature distribution in a spherical body 90 + =0 It is defined as r2 dr a)obtain the temperature distribution T (r) b)Determine the boundary conditions. Find the maximum temperature T (max)arrow_forward
- 3-78E Steam exiting the turbine of a steam power plant at 100°F is to be condensed in a large condenser by cooling water flowing through copper pipes (k = 223 Btu/h ft. °F) of inner diameter 0.4 in. and outer diameter 0.6 in. at an average temperature of 70°F. The heat of vaporization of water at 100°F is 1037 Btu/lbm. The heat transfer coefficients are 1500 Btu/h ft² °F on the steam side and 35 Btu/h ft² °F on the water side. Determine the length of the tube required to con- dense steam at a rate of 120 lbm/h. Answer: 1148 ft Steam, 100°F 120 lbm/h Liquid water FIGURE P3-78E Cooling waterarrow_forwardQuestion 4 The window of a room is made of 5 mm thick glass which has a thermal conductivity of 1.4 W/m-K. A heater is used to maintain the room temperature at 22 °C. Take the convection heat transfer coefficients on the outer surface of the window to be 12 W/m²-K. Take appropriate assumptions while solving this problem. (a) T₁-15°C T↑ -A= 1m x 3m 3m², k=1.4W/m-K Find the outside temperature? -T₂=5°C * L=0.005m Figure Q2arrow_forwardA current of 200 A is passed through a stainless steel wire (k = 19 W/m.K) 3 mm in diameter. The resistivity of the steel is 70x10^(-6) ohm.cm, and the length of the wire is 1 m. The wire is submerged in a liquid at 383 K and experiences a convection heat transfer coefficient of 4 kW/m^2. K. The center temperature (in K) of the wire isarrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning