A double-pipe heat exchanger is used to cool oil. Cold water flows through the small pipe, while oil flows through the outside of the samll pipe. The oil is cooled from 107℃ to 32℃, while the water is heated from 17℃ to 60℃, so the logarithmic mean temperature difference is?
A. 28.2 ℃
B. 48.5 ℃
C. 51.2 ℃
D. 23.4 ℃
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The temperature correction factor is determined by the dimensionless factors P and R, what is the physical meaning of P?
A. The ratio of the actual temperature rise of the cold fluid and the maximum temperature rise that can be achieved theoretically
B. The ratio of the thermal capacity of the clod and hot fluid
C. The ratio of the actual temperature drop of the hot fluid and the maximum temperature drop that can be achieved theoretically
Do not have physical meaning
For a heat exchanger, the inlet and outlet temperature for the hot fluid is 130℃ and 60℃, the inlet and outlet temperature for the cold fluid is 30℃ and 70℃, so the effectiveness of the heat exchanger is ?
A. 0.8
B. 0.7
C. 0.9
D. 0.6
what is the biggest difference between the design calcluation and check calculation for the heat exchanger?
A. Whether kA is known or not
B. Whether heat transfer area A is known or nt
C. Wether the flow rate of the cold fluid is known or not
D. Wether the temperature of the cold fluid is known or not
The temperature correction factor is determined by the dimensionless factors P and R, what is the physical meaning of R?
A. The ratio of the actual temperature rise of the fluid 1 and the maximum temperature rise that can be achieved theoretically
B. The ratio of the specific heat of fluid 1 and fluid 2
C. The ratio of the actual temperature rise of the fluid 2 and the maximum temperature rise that can be achieved theoretically
D. The ratio of the thermal capacity of fluid 1 and fluid 2
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