Question 2a) Give the Stefan Boltzman equation and define each term.[4]b) A electric room heater (radiator) element is 25 cm long and 4 cm in diameter. The element dissipates heat to the surroundings at 1500 W mainly by radiation, the surrounding temperature being 15°C. Determine the equilibrium temperature of the element surface.[4]c) A composite cylinder consists of 10 cm radius steel pipe of 25 mm thickness over which two layers of insulation 30 mm and 35 mm are laid. The conductivities are 25 W/mK, 0.25 W/mK and 0.65 W/mK. The inside is exposed to convection at 300°C with h 65 W/m2K.The outside is exposed to air at 30°C with h 15 W/m2K. Determinei. the heat loss/m,the interface temperatures.ii. The overall heat transfer coefficient.[4][4][2]

Question 2a) Give the Stefan Boltzman equation and define each term.[4]b) A electric room heater (radiator) element is 25 cm long and 4 cm in diameter. The element dissipates heat to the surroundings at 1500 W mainly by radiation, the surrounding temperature being 15°C. Determine the equilibrium temperature of the element surface.[4]c) A composite cylinder consists of 10 cm radius steel pipe of 25 mm thickness over which two layers of insulation 30 mm and 35 mm are laid. The conductivities are 25 W/mK, 0.25 W/mK and 0.65 W/mK. The inside is exposed to convection at 300°C with h 65 W/m2K.The outside is exposed to air at 30°C with h 15 W/m2K. Determinei. the heat loss/m,the interface temperatures.ii. The overall heat transfer coefficient.[4][4][2]

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.

Chapter2: Steady Heat Conduction

Section: Chapter Questions

Problem 2.22P: A cylindrical liquid oxygen (LOX) tank has a diameter of 1.22 m, a length of 6.1 m, and...

See similar textbooks

Similar questions

1. The following questions concern two hypothetical materials, R for the red curve and B for the blue curve, (see figure below) showing the net interatomic forces as a function of interatomic separation. (6") a) Which material will have a higher modulus of elasticity, and why? b) Which material will have a higher melting point, and why? c) Which material will have a larger coefficient of thermal expansion, and why? Hint: You can integrate graphically. ro Separation Force
Use the first image to solve two part question
SHOW YOUR COMPLETE SOLUTION
3.4 Estimate the rate of heat loss due to radiation from a covered pot of water at 95 ° C. How does this compare with the 60 W that is lost due only to convection and conduction losses? What amount of energy input would be needed to maintain the water at its boiling point for 30 minutes? The polished stainless steel pot is cylindrical, 20 cm in diameter and 14 cm high, with a tight-fitting flat cover. The air temperature in the kitchen is about 25 ° C. State any assumptions you make in deriving your estimates
Hello, I am a mechanical engineering student and want to upload this question as I have an exam in early June about thermodynamics. I have been given a question that will help me answer my exams in June. Please could you answer showing step by step guidance on how to answer this question with the formula clearly shown. Thank you very much
A heating element made of tungsten wire connected to a large battery that has negligible internal resistance. When the heating element reaches 80.0°C, it consumes electrical energy at a rate of 480 W. Assume that the temperature coefficient of resistivity has the value given in Table 25.2 in the textbook and that it is constant over the temperature range in this problem. In the equation R(T) = Ro [1 + a(T - To)] take To to be 20.0°C. Part A What is its power consumption when the temperature of the heating element is 110.0°C? Express your answer with the appropriate units. P = Submit Value Provide Feedback Request Answer Units ?
Four infinite, parallel, black, opaque plates transfer heat by radiation as shown in figure 1.19. Find T2 and T3 [T2= 75.53°C]. This is a heat transfer problem from the textbook A Heat Transfer Textbook fifth edition
My buddy is starting to get hypothermic (body temperature 306 K) during an epic backcountry ski adventure. Since I'm quite warm (body temperature 310 K), I decide to get in a sleeping bag with him to try and warm him up. What heat transfer mechanism will be most responsible for heating him up? For simplicity, ignore any internal temperature differences across my body (that is, assume my skin temperature is also 310 K). Use numbers to support your answer (for human skin, you can use the following values: surface area A = 1:50 m2, emissivity = 0:970, thickness d = 0:0250 m, thermal conductivty 0:200 JmsK)
need help with part D
What’s the correct answer for this please?
(3) The thermal conductivity of helium at 400 K is 0.176 W m-! K-1. Knowing only this datum, estimate the thermal conductivity of helium at 800 K. Compare your estimate to the value obtained from the figure below. 06 as 02 01 co CO.N A HCI Cl, 200 400 00 Temperature, K 1200 1400 600 What do you conclude about the equation that you used for your estimate?
4. A wall with an area of 10 m² is made of a 2 cm thickness of white pine (k=0.113 W/1-deg C) followed by 10 cm of brick (k=0.649 W/m-deg C). The pine is on the inside where the temperature is 30 deg C while the outside temperature is 10 deg C. Assuming equilibrium conditions exist, what is the temperature at the interface between the two metals.