How do you calculate the temperature drop?

I recommend a reference book in the field of chemical engineering, namely \"Principles of Chemical Engineering.\" I’m not sure what practical value there is in performing these calculations.

Lowering blood pressure also lowers body temperature； Heat dissipation will lower the temperature ； It is estimated that the values for pressure reduction and temperature lowering should be higher (guess 10°C), while heat dissipation depends on many factors such as ambient temperature, transmission length, and whether insulation is used or not ； Once the conditions are met, one can only use software to do the calculations.

Senior, the conditions he offered can’t be calculated for now!

These days, many newcomers to the field, no matter what the situation is, start by dealing with calculations, software, standards, regulations, and so on. It’s certainly acceptable to conduct research in a design role; however, it’s really too early to focus on such things in an operational role.

There’s nothing wrong with seeking the truth; but if one doesn’t delve into it thoroughly, what’s the difference from being idle? Knowledge and experience are generated and accumulated through one problem after another. Well, back to the topic at hand. Now let’s analyze this issue. This problem can actually be simplified as a change from state point 1 (5 MPa, 25°C) to state point 2 (0.5 MPa, temperature unknown). Assumption 1: The temperature of the oxygen is not high, being similar to the outdoor temperature; therefore, this process can be considered adiabatic, meaning that no heat is lost and no heat is transferred from the outside into the pipeline. Assumption 2: Ignore the effect of friction between the gas and the pipe walls on the enthalpy of oxygen, that is, ignore the effect of pipeline pressure drop on the enthalpy of oxygen. Therefore, this process can be simplified to an adiabatic expansion process. The adiabatic expansion from state point 1 (5 MPa, 25°C) results in state point 2 (0.5 MPa, with constant enthalpy); determine the temperature t2 of state point 2. First, the enthalpy value at state point 1 is calculated to be 258.79 kJ/kg; then, using 0.5 MPa and 258.79 kJ/kg, the temperature is determined to be t2 = 13.15°C. Analyze reasonably, simplify problems, and make good use of tools. By accident, I became the fastest man in the office again. Note: This feature has not yet been released in the chemical calculation app; it is expected to be available in May 2020.

If you had such qualities, I guess this problem wouldn’t exist. :)

I agree with you; it’s often those on the front line who have firsthand experience with actual operations. If one doesn’t understand the principles behind these processes, how can they improve their knowledge and skills, let alone bring about improvements in the manufacturing processes? PS: It’s clear that you’ve put a lot of effort into developing this app; I’m looking forward to it

Checked using NISTREFPROP, and the data is extremely accurate, without any errors

The saying that practice is the sole criterion for testing truth holds true at any time! Liking for you! ! ! In actual work, the ability to consider one step ahead, plan two steps further, and calculate three or four steps in advance is not something everyone can do; only the truly skilled experts can achieve this. Just as in everyday work, there are people who simply do their tasks without wanting to know why they are doing them; you still need to explain these things to them. If one wants to ask, they will naturally ask!

This post was last edited by A Chao syc62100 on 2020-4-19 11:39. During adiabatic expansion, given the type of gas, pressure, and temperature, how can the enthalpy value be calculated? In the book, it is stated that H=U+PV; that’s the principle. Is there a specific formula for this? I’d like to know why, thank you!