Question
(a) A thermos flask is made up of two concentric cylinders of diameter 75 mm and 88 mm and length 250 mm. The space between
(a) A thermos flask is made up of two concentric cylinders of diameter 75 mm and 88 mm and length 250 mm. The space between the two cylinders is evacuated to reduce the heat loss. The outer surface of the inner cylinder and the inner surface of the outer cylinder are couted with silver paint. The emissivity of both the polished surfaces is 0.025. If the contents of the thermos flask are at 96 C and the ambient temperature is 27 C. calculate the heat loss from the flask. (b) If the space between the two cylinders is replaced by cork, what thickness of cork will be required to have the same heat loss as the vacuum condition. Thermal conductivity of cork = 0.042 W/mK. (The walls of the thermos flask can be assumed to be a flat plate).
Step by Step Solution
There are 3 Steps involved in it
Step: 1
Get Instant Access to Expert-Tailored Solutions
See step-by-step solutions with expert insights and AI powered tools for academic success
Step: 2
Step: 3
Ace Your Homework with AI
Get the answers you need in no time with our AI-driven, step-by-step assistance
Get Started