Question

The Prandtl number, Pr, is a dimensionless group important in heat transfer. It is defined as Pr - Cp*mu/k where Cp is the heat capacity of a fluid, mu is the fluid viscosity, and k is the fluid thermal conductivity. For a given fluid, Cp 0.66 J/(g * deg C), k 0.36 W/(m * deg C), and mu 1896 lbm (ft * h}. Determine the value of the Prandtl number for this fluid

Answer 1

The Prandtl number for this example is 14,553.

Step-by-step explanation:

The Prandlt number is defined as:

`Pr=(C_(p)*\mu)/(k)`

To compute the Prandlt number for this case, is best if we use the same units in every term of the formula.

`\mu=1896 (lbm)/(ft*h)*(1000 g)/(2.205 lbm)*(3.281 ft)/(1 m)*(1h)/(3600s)  =7938 (g)/(m*s)`

Now that we have coherent units, we can calculate Pr

`Pr=(C_(p)*\mu)/(k)=0.66*7938/0.36=14553`