Nusselt Number Equation Simplification?

In summary, the conversation discusses converting between the Nusselt number, Reynolds number, and Prandtl number equations for calculating heat transfer coefficients in fluid flow. The first equation is a combination of the latter two, while the second equation is the definition of the Nusselt number. To convert between the two, the definitions of Reynolds and Prandtl numbers can be used, allowing for an expression to be derived in terms of fluid properties.
  • #1
dillonmhudson
49
0

Homework Statement


See the picture for the homework problem:
http://i41.tinypic.com/2drk2x.png


Homework Equations



I'm having trouble converting between the first equation and the second one.

I understand that Nu_x=h_x*x/k
Re = rho*v*x/visc
Pr = c_p*visc/k

But how the heck do I convert all that to the second equation?

Thanks


The Attempt at a Solution



As above, I combined the equations together but I don't know where the T (temperature) comes in, or how you can simplify an equation when you have a square root and a cube root.
 
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  • #2


Hello,

It looks like you are trying to convert between the Nusselt number (Nu), Reynolds number (Re), and Prandtl number (Pr) equations. The second equation you have shown is the definition of the Nusselt number, which is used to calculate heat transfer coefficients in fluid flow. The first equation is a combination of the Reynolds and Prandtl numbers, which are also important in determining heat transfer coefficients.

To convert between the two equations, you can use the definitions of the Reynolds and Prandtl numbers to substitute into the first equation. This will give you an expression for the Nusselt number in terms of the velocity (v), density (ρ), heat capacity (c_p), thermal conductivity (k), and viscosity (μ) of the fluid. You can then rearrange this equation to solve for the temperature (T) and simplify as needed.

I hope this helps. Good luck with your homework!
 

Related to Nusselt Number Equation Simplification?

1. What is the Nusselt Number Equation?

The Nusselt Number Equation is a dimensionless quantity used in heat transfer calculations to determine the convective heat transfer coefficient between a fluid and a solid surface.

2. How is the Nusselt Number Equation simplified?

The Nusselt Number Equation can be simplified by using the appropriate correlations and assumptions for the specific flow and heat transfer conditions. It can also be simplified by reducing the number of variables and simplifying the mathematical expressions.

3. What are the assumptions made in simplifying the Nusselt Number Equation?

The assumptions made in simplifying the Nusselt Number Equation may vary depending on the specific problem, but some common assumptions include: steady-state conditions, constant fluid properties, and a constant heat transfer coefficient.

4. Can the Nusselt Number Equation be simplified for all types of flow and heat transfer conditions?

No, the Nusselt Number Equation cannot be simplified for all types of flow and heat transfer conditions. It is important to use the appropriate correlations and assumptions for the specific problem in order to accurately simplify the equation.

5. How does the simplification of the Nusselt Number Equation affect the accuracy of heat transfer calculations?

The simplification of the Nusselt Number Equation can affect the accuracy of heat transfer calculations, as it may introduce some errors due to the assumptions made. However, simplifying the equation can also make the calculations more manageable and easier to solve.

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