A small oven consists of a cubical box of dimension
(a) Find the following view factors: F12, F13, F21, F31, F23, F32, F33.
(b) Determine the temperature of the floor and the net rate of heat transfer leaving the sphere due to radiation. Is the sphere under steady-state conditions?
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Fundamentals of Heat and Mass Transfer
- Question 5: Z=62 a. An iron sphere of mass (Z + 300)g is kept in a container having boiling water (100 °C). If the temperature of the sphere is 25.5°C, how much heat energy is absorbed by the iron sphere? Consider the specific heat of iron as 452J/kg. b. The wall of an industrial furnace is constructed from (Z + 3) cm thick fireclay brick having a thermal conductivity of 1.7 W/mK. Measurements made during steady-state operation reveal temperatures of 530°C and 375°C at the inner and outer surfaces, respectively. Find the rate of heat loss through a wall which is (Z + 5) cm by (Z + 3) m on a side.arrow_forwardThe diagram below illustrates a simplified version of the Jet Propulsion Laboratory's 25-ft space simulator chamber. Within it, tests are run for deep space probes and their components. In this particular experiment, a sensor assembly with its housing is placed inside. The sensor-housing electronics create heat such that q=3181.0 W exits the assembly's top surface into the chamber. The chamber itself is under vacuum, and its walls are at cryogenic temperatures to simulate conditions in space. Surfaces 1 and 2 are flat. Assume they are flush. The top surface of the chamber, Surface 4, can be approximated as a perfectly insulated, flat ceiling. The exposed surface of the floor, Surface 2, is a black, donut- shaped surface. Additional surface information can be seen below, including various parameters and dimensions. Assume all surfaces are opaque and diffuse, and conditions are at steady-state. PARAMETERS & DIMENSIONS Surface 1: A = 7.07 m²; diameter d; = 3 m; &₁ = 0.5; Surface 2: A₂ =…arrow_forwardA box made of copper plate with outside dimensions of 5 ft by 5 ft by 6-in.is suspended horizontally in a large room where the air and wall temperaturesare 80°F. The box contains a heating coil which maintains a temperature of500 °F on all external surfaces. What is the total heat loss from the box inBtu/hr.arrow_forward
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- On a mild Saturday morning while people are working inside, the furnace keeps the temperature inside the building at 23°C. At noon the furnace is turned off, and the people go home. The temperature outside is a constant 14°C for the rest of the afternoon. If the time constant for the building is 3 hr, when will the temperature inside the building reach 19°C? If some windows are left open and the time constant drops to 2 hr, when will the temperature inside reach 19°C? If the time constant for the building is 3 hr, the temperature inside the building will reach 19°C about hr after noon. (Round to the nearest tenth as needed.) If the time constant for the building drops to 2 hr, the temperature inside the building will reach 19°C about (Round to the nearest tenth as needed.) hr after noon. Carrow_forwardSipho’s mother is making a fire in the stove inside a shack using coal. A fan is used to extract the flue gasfrom the fire via a chimney made of zinc material. The wall thickness of Chimney is L=4mm and the walltemperature of the chimney on the flue gas side is T_si=60˚C. Sipho, playing outside next to the chimneyexperiences an ambient temperature of 20˚C. The surrounding temperature is T_sur=35˚C and the emissivityis ε=0.95. Assume the convection coefficient is 20W/m2K and the chimney is grey material.Under these conditions determine the outer surface (air side) temperature T_so=? of the chimney.arrow_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_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning