Surface cooling - Rayleigh, Prandtl and Grashof numbers

In summary, surface cooling is the process of cooling down a surface, such as a solid object or liquid. Rayleigh, Prandtl, and Grashof numbers are dimensionless numbers that describe the behavior of fluids experiencing temperature changes and are important in quantifying the rate of surface cooling. These numbers affect surface cooling by determining the rate of heat transfer from the surface to the surrounding fluid, with higher values resulting in faster cooling. The typical values for these numbers vary but are usually in the range of 10^2 to 10^7 for Rayleigh number, 10^-3 to 10^3 for Prandtl number, and 10^3 to 10^11 for Grashof number. To optimize surface
  • #1
Roger44
80
1
Hello,
I am trying to calculate the surface cooling rate from the sides of a round tin can using Rayleigh, Prandtl and Grashof numbers but I'm getting a ridiculously high result, and I'm hoping someone could run through my numbers to tell me where I'm going wrong.

Posting my question is going to take a bit of time, so could you let me know if you're willing to tackle this one.

Thanks
Roger
 
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  • #2
OK, found it.
I took k of the metal instead of k of air.
Sorry
 

1. What is surface cooling?

Surface cooling is the process by which a surface, such as the surface of a solid object or the surface of a liquid, is cooled down.

2. What are Rayleigh, Prandtl, and Grashof numbers?

Rayleigh, Prandtl, and Grashof numbers are dimensionless numbers that are used to describe the behavior of fluids when they experience temperature changes or temperature gradients. These numbers are important in the study of surface cooling because they help to quantify the rate at which a surface cools down.

3. How do Rayleigh, Prandtl, and Grashof numbers affect surface cooling?

Rayleigh, Prandtl, and Grashof numbers affect surface cooling by determining the rate at which heat is transferred from the surface to the surrounding fluid. Higher values of these numbers indicate a higher rate of heat transfer, which results in faster cooling of the surface.

4. What are the typical values for Rayleigh, Prandtl, and Grashof numbers in surface cooling?

The typical values for Rayleigh, Prandtl, and Grashof numbers in surface cooling vary depending on the specific system being studied. However, they are usually in the range of 10^2 to 10^7 for Rayleigh number, 10^-3 to 10^3 for Prandtl number, and 10^3 to 10^11 for Grashof number.

5. How can the values of Rayleigh, Prandtl, and Grashof numbers be adjusted to optimize surface cooling?

The values of Rayleigh, Prandtl, and Grashof numbers can be adjusted by changing the properties of the fluid or the surface, such as the temperature difference between the surface and the fluid, the fluid viscosity, or the surface geometry. By optimizing these values, the rate of heat transfer can be increased, resulting in more efficient surface cooling.

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