【Daily Question】Theoretical Foundation 2021.1.09
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Multiple-choice question: The question is shown in the image ( ). Answer: C. Hint: An additional reward will be given to those who can explain the solution process; the answer can be submitted there
This post was last edited by h20090630 on 2021-1-9 at 17:13. C: Since the heat absorbed by the cold fluid is equal to the heat released by the hot fluid, it follows that: By substituting the values, the outlet temperature of the cold fluid is 25°C. Then, when flowing downstream, Δt′=40℃ and Δt″=10℃ ； During reverse flow, Δt′=30℃ and Δt″=20℃. Logarithmic mean temperature difference: Therefore, the ratio of the average logarithmic temperature differences for counterflow to co-flow is: Δtm (counterflow) / Δtm (co-flow) = 1.14.