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 0.5 J/(g * deg C), k 0.2 W/(m * deg C), and mu 2200 lbm (ft* h}. Determine the value of the Prandtl number for this fluid. Please keep two significant figures in your final answer

Answer 1

Pr = 2273.58

Step-by-step explanation:

• Pr = Cp*μ/κ

∴ Cp = 0.5 J/g.°C

∴ κ = 0.2 W/m.°C * ( J/s / W ) = 0.2 J/s.m.°C

∴ μ = 2200 Lbm/ft.h * ( 453.592 g/Lbm ) * ( ft / 0.3048 m ) * ( h/3600 s )

⇒ μ = 909.433 g/m.s

⇒ Pr = ((0.5 J/g.°C )*( 909.433 g/m.s )) / 0.2 J/s.m.°C

⇒ Pr = 2273.58