Thermodynamics HW Solutions 338

Thermodynamics HW Solutions 338 - Chapter 4 Transient Heat...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 4 Transient Heat Conduction 4-64 An area is subjected to cold air for a 10-h period. The soil temperatures at distances 0, 10, 20, and 50 cm from the earths surface are to be determined. Assumptions 1 The temperature in the soil is affected by the thermal conditions at one surface only, and thus the soil can be considered to be a semi-infinite medium with a specified surface temperature. 2 The thermal properties of the soil are constant. Properties The thermal properties of the soil are given to be k = 0.9 W/m. C and = 1.6 10-5 m 2 /s. Analysis The one-dimensional transient temperature distribution in the ground can be determined from + + = k t h t x erfc k t h k hx t x erfc T T T t x T i i 2 exp 2 ) , ( 2 2 Soil T i = 10 C Winds T =-10 C where 1138 7 . 33 7 . 33 C W/m. 0.9 ) s 3600 10 )( s / m 10 (1.6 C)...
View Full Document

Ask a homework question - tutors are online