Is there something wrong with the viscosity unit in the Chemical Engineering Handbook?
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Looking at the table, we know that the viscosity of water is around 1. The viscosity unit given in the picture is 1MPa·s. The viscosity of water in Baidu Encyclopedia is 1mPa·s. There is a big difference between the two units. Which one should be used?
The unit of absolute viscosity is Pascal·second (Pa·s). In practical engineering applications, the unit is mostly milliPa·second (mPa·s), 1Pa·s=1000 mPa·s. If you see "MPa·s" in the manual, it may be a mistake, because under normal temperature and pressure, the viscosity of most liquids (such as water) generally does not exceed dozens of mPa·s. According to most scientific information, including Baidu Encyclopedia, the viscosity of water at 20 degrees Celsius is approximately 1.002mPa·s. So according to your description, the viscosity value of water should be 1mPa·s, not 1MPa·s. Of course, in order to ensure the accuracy of the results, it is recommended to check directly with the author or publisher of the manual to obtain the correct information. .
This post was last edited by qugd on 2023-10-26 16:31. If it is a direct reading, it should be marked incorrectly when entering it. The correct way to write it is mPa.s, with the prefix marked M, which is a billion times different. The viscosity of water is basically the magnitude of the previous unit. But this graph needs to be calculated based on the found X and Y. Please also check some factors in the calculation formula.
What is said above is absolutely true. Don’t worry, just look up the viscosity of water in the Appendix of Principles of Chemical Engineering, and you’ll know what’s right or wrong by comparing it.