. Air and water in a cross flow heat exchanger. The fluids do not come

In summary, the conversation is about using FLUENT for a cross flow analysis in a heat exchanger with air and water. The participant is seeking help with assigning different fluid properties for different boundary conditions and determining the temperature drop. Another participant suggests using empirical relations for heat transfer and mentions the availability of equations for shell and tube heat exchangers in API standards. The original participant thanks the other for their advice and plans to use it.
  • #1
sashankhrao
19
0
Hi,

I am trying to do a cross flow analysis in FLUENT. Air and water in a cross flow heat exchanger. The fluids do not come in contact. I have modeled and meshed the geometry in GAMBIT. Could someone pls help me with the steps in FLUENT as to how to assign different fluid properties for different boundary conditions and so on. I need to det the temp. drop of air and water.

Thanks!
 
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  • #2


You'll probably be better off just using impirical relations to get heat transfer. In CFX at least, in order to get decent heat transfer numbers, you need the heat transfer coefficients.

There are fairly good equations for shell and tube heat exchangers, check the API standards.
 
  • #3


Hi,

Sorry for the late reply. Thanks a lot for answering my question. I'll take your advice of using impirical relations.

Sashankh
 

1. How does a cross flow heat exchanger work?

A cross flow heat exchanger works by transferring thermal energy between two fluids that flow perpendicular to each other. One fluid flows through a series of tubes, while the other flows across the tubes in a perpendicular direction. The two fluids do not mix, but heat is transferred through the walls of the tubes.

2. What are the benefits of using a cross flow heat exchanger?

The main benefit of using a cross flow heat exchanger is its efficiency in transferring heat between two fluids. The perpendicular flow of the fluids allows for a large surface area for heat transfer, resulting in a more efficient exchange. It also allows for a compact design, making it useful in a variety of applications.

3. What are the common types of fluids used in a cross flow heat exchanger?

The most common types of fluids used in a cross flow heat exchanger are air and water. Air is often used as the fluid flowing through the tubes, while water is used as the fluid flowing across the tubes. Other common fluids include refrigerants, oils, and various gases.

4. How do you calculate the heat transfer in a cross flow heat exchanger?

The heat transfer in a cross flow heat exchanger can be calculated using the heat exchanger effectiveness method. This method takes into account the inlet and outlet temperatures, flow rates, and heat capacity of the fluids. The effectiveness can then be used to calculate the actual heat transfer rate.

5. What are the common applications of a cross flow heat exchanger?

A cross flow heat exchanger is commonly used in HVAC systems, power plants, and industrial processes. It is also used in refrigeration and air conditioning systems to transfer heat between the refrigerant and the air. Other applications include heat recovery systems and thermal management in electronic devices.

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