The issue of the heat transfer coefficient
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What is the heat transfer coefficient of this shell-and-tube heat exchanger (for steam and diesel) approximately? What are the heat transfer coefficients for shell-and-tube exchangers using 0# diesel and -35# diesel? This post was last edited by jia717 on 2009-4-19 at 22:09.]
The heat transfer coefficient is calculated based on the dimensions of the heat transfer tubes and the thermal resistance due to fouling inside and outside these tubes. Since the structural design and materials of the heat exchanger are fixed, the difference in thermal resistance due to fouling between 0# diesel and -35# diesel is minimal, and thus their heat transfer efficiency is also similar. Additionally, the heat transfer coefficient from diesel to water is around 350 W/m2.K. This post was last edited by zx9527007 on 2009-4-19 22:57.]
I have some objections to what was said above. I believe the heat transfer coefficient is highly related to the medium; different media have different physical and chemical properties, and their thermal conductivity varies greatly. Therefore, in addition to being influenced by the structure of the heat exchanger, it is also affected by the medium.
The heat transfer coefficient must be related to the medium, right? I don’t understand what the person on floor 2 said
I don’t know what the theory is regarding where the second floor is. Don’t mislead the young people.
The appendix to the book on heat exchanger design and principles provides recommended value ranges for the overall heat transfer coefficients corresponding to the fluids on the shell and tube sides; in your case, this value is likely to be relatively high. I checked again; there is a table on page 69 of the second volume of the heat exchanger design manual compiled by Oi Eihana, which provides recommended values for the overall heat transfer coefficient. For your specific operating conditions, the overall heat transfer coefficient should be between 100 and 300. This book can be downloaded from the resource section, and it’s also mentioned in the post I posted: http://bbs.hcbbs.com/thread-405577-1-1.html. This post was last edited by vivo1314 on 2009-4-19 at 22:39
It has been edited again; if the thermal resistance due to dirt is not taken into account, there isn’t much difference.
The calculation of the heat transfer coefficient is related to the properties of the medium, the structure of the heat exchanger, as well as the allowable pressure drop
The heat transfer coefficient is related to both the structure and the properties of the fluid. The structure determines the flow velocity of the fluid, the degree of turbulence, and the Reynolds number, while the properties of the fluid determine the Prandtl number and the Reynolds number. All these factors need to be taken into consideration together