Estimate the heat loss from human body of 36 C temperature by convection and radiation. Consider the following assumptions: a. wall is black body at temperature b. human body emissivity c. air bulk temperature d. average approx. body surface area e. convective coefficient f. heat conduction thru feet to the floor 25 C 0.85 25 C 2.15 m² 7.5 W/m² C negligible

Estimate the heat loss from human body of 36 C temperature by convection and radiation. Consider the following assumptions: a. wall is black body at temperature b. human body emissivity c. air bulk temperature d. average approx. body surface area e. convective coefficient f. heat conduction thru feet to the floor 25 C 0.85 25 C 2.15 m² 7.5 W/m² C negligible

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 1.29P: 1.29 A spherical interplanetary probe with a 30-cm diameter contains electronic equipment that...

See similar textbooks

Similar questions

1.29 A spherical interplanetary probe with a 30-cm diameter contains electronic equipment that dissipates 100 W. If the probe surface has an emissivity of 0.8, what is its surface temperature in outer space? State your assumptions in the calculations.
1.47 A flat roof is modeled as a flat plate insulated on the bottom and placed in the sunlight. If the radiant heat that the roof receives from the sun is , the convection heat transfer coefficient between the roof and the air is 12 W/m2 K, and the air temperature is , determine the roof temperature for the following two cases: (a) Radiative heat loss to space is negligible, (b) The roof is black and radiates to space, which is assumed to be a black- body at 0 K.
Please solve both parts with handwriting please need with correct answer need awesome answer solve both handwriting i requested to u. Part6. An exposed 8 cm external diameter, 20 m long hot-water pipe at 80°C is losing heat to the surrounding (outdoor) air by natural convection. The average outdoor temperature is 5°C. The heat transfer coefficient is 25 W/m2°C. What is the heat loss by natural convection, in kW? A. 9.4 W B. 10.0 W C. 10.4 W D. 11.4 W Part7. A spherical ball with a diameter of 10 cm has an outer surface that is maintained at a temperature of 200°C. It is suspended in the middle of a room that has an average temperature of 20°C. If the surface emissivity is 0.8, determine the rate of radiative heat transfer from the ball to the room in W. (Choose the nearest value) A. 2.3 W B. 4.5 W C. 19.4 W D. 60.8 W
Q2: A person of skin temp. of 30 K and body surface area 1.75 cm2, find: (a): net total power if he receives radioactive power from the surrounding walls 22 °C would be about 735 w. (6 = 5.7 x 10 12 w/cm) (b): The emissivity of surrounding walls. Good luck
V:01 Expert Q&A Done Question 1: In your own words, write down the differences between thermodynamic and heat transfer. (3 Marks) Question 2: Estimate the heat loss per square metre of surface through a brick wall 0.5 m thick when the inner surface is at 400 K and the outside surface is at 300 K. The thermal conductivity of the brick may be taken as 0.7 W/mK. (2 Marks) Question 3: A furnace is constructed with 0.20 m of firebrick, 0.10 m of insulating brick, and 0.20 m of building brick. The inside temperature is 1200 K and the outside temperature is 330 K. If the thermal conductivities are as shown in the figure below, estimate the heat loss per unit area. (5 Marks) 1200 K 330 K Insulating brick X-0.10m k= 0.21 Ordinary brick X=0.20 m Fire brick X= 0.20 m k= 1.4 k= 0.7 (W/mK)
A steam pipe with outside diameter 10 mm, passes through a room, the surface temperature of the pipe is 100 °C and the air is at 25 °C. Convection coefficient is 15 W/ m2.K. The heat transfer from the pipe per unit length: Select one: a. None of the mentioned b. 350 W/m С. 350 W d. 250 W/ m e. 25 W
105 W/m3 heat is uniformly generating within a 4 cm thick slab. The slab is exposed to ho = 10 W/m2K and To = 20 °C ambient conditions from its both sides. What is the surface temperature of the slab? A. 420 °C B. 200 °C C. 220 °C D. 100 °C
FIll in the blanks: A slab 0.25 m thick with thermal conductivity of 45 W/m-K receives heat from a furnace at 500 K both by convection and radiation. The convection coefficient has a value of 50 W/m²- K. The surface temperature is 400 K on this side. The heat is transferred to surroundings at T, both by convection and radiation. The convection coefficient on this side is 60 W/m2-K. Determine the surrounding temperature. K.
GChoose the right answer 1. The temperature profile for steady hest conduction through a plane wall of constant thermal conductivity is a. logarithmic b. parabolic 2. A brick wall (k-0.75 W/mK ) transmits $02 of heat loss through another wall (k-0.25 W/mK, x-100 mm). If the temperature difference across both walls is the same, the thickness of the brick wall would be a.150 mm c. linear 6T b. 240 mm c. 300 mm d. 375 mm 3. The maximum temperature at the center of the solid sphere of radius R having heat generation q (W/m') is given by g'R +9R b. T, + 4k T+9R 6k d. T+9R 8k a. 2k C. 4. The internal thermal resistance of a solid can be ignored if the Biot number is less than a. 1 b. 0.5 c. 0.1 d. Fourier number 5. The ratio of heat transfer of a fin to the heat transfer without fin is referred to as a. fin resistance b. fin efficieney efin effectiveness d. fin conductance.
A finned surface has been added to cool an electronic part. The surface temperature of the electronic part in contact with the fins is 60 ° C, the convection coefficient between the environment and the finned surface is 40 W / m².K and the heat conduction coefficient for the fin material (aluminum) is 180 w / m.K. a. If the electronic part has wings or no blades, the amount of heat per unit time (W) thrown into the environment, b. Find out wing effectiveness and efficiency?
Inner diameter 30 cm, outer diameter 40 cm and heat conduction coefficient 20 W / m ∙ a cylindrical pipe with oC Take it. 25 W / m3 uniformly on the pipe wall There is a constant rate of heat generation. Tube inner surface 75 oC and outer surface temperature is 95oC. a) You can get a general correlation all over the world in the pipe (Continuous regime). b) Temperature calculation address from the midpoint of the pipe wall.
A steam pipe with outside diameter 10 mm, passes through a room, the surface temperature of the pipe is 100 °C and the air is at 25 °C. Convection coefficient is 15 W/ m2.K. The heat transfer from a tube of length 5 m is: Select one: a. 1767 W b. 1767 W/ m c. 1767 W /m2 d. 176 W e. 1765 W