Q1: Consider a hot automotive engine, which can be approximated as 0.40m wide, and 0.8m long rectangular block. The bottom surface of the block is at a temperature of 80°C and has an emissivity of 0.95. The ambient air is at 20°C, and the road surface is at 25°C. Determine the rate of heat transfer from the bottom surface of the engine block by convection and radiation as the car travels at a velocity of 80 km/h. Assume, the flow to be turbulent over the entire surface because of the constant agitation of the engine block. k=0.02735 W/m.°C v=1.798×10° m³/s Air properties at Tf= 50 °C: Pr=0.7228 Answer: Qcom = 1363 W, Qrad = 132 W, Quotal= 1495 W %3D

Q1: Consider a hot automotive engine, which can be approximated as 0.40m wide, and 0.8m long rectangular block. The bottom surface of the block is at a temperature of 80°C and has an emissivity of 0.95. The ambient air is at 20°C, and the road surface is at 25°C. Determine the rate of heat transfer from the bottom surface of the engine block by convection and radiation as the car travels at a velocity of 80 km/h. Assume, the flow to be turbulent over the entire surface because of the constant agitation of the engine block. k=0.02735 W/m.°C v=1.798×10° m³/s Air properties at Tf= 50 °C: Pr=0.7228 Answer: Qcom = 1363 W, Qrad = 132 W, Quotal= 1495 W %3D

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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Question

H.W.
Q1: Consider a hot automotive engine, which can be approximated as 0.40m wide, and 0.8m
long rectangular block. The bottom surface of the block is at a temperature of 80°C and has
an emissivity of 0.95. The ambient air is at 20°C, and the road surface is at 25°C. Determine
the rate of heat transfer from the bottom surface of the engine block by convection and
radiation as the car travels at a velocity of 80 km/h. Assume, the flow to be turbulent over
the entire surface because of the constant agitation of the engine block.
k = 0.02735 W/m.°C
v=1.798×10* m²/s
Air properties at Tf= 50 °C:
Pr = 0.7228
Answer: Qcony = 1363 W, Qrad = 132 W, Qotal = 1495 w
Hint: Use the correlations (equations) of average Reynold number (ReL).
L = 0.8 m
Engine block
Air
V, = 80 km/h
T. = 20°C
T; = 80°C
ɛ = 0.95

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