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Heat Transfer - Engineering

Q1:

For flow over a flat plate, the ratio of thermal boundary layer thickness, 'xt' and hydrodynamic boundary layer thickness 'x' is equal to (where, NPr = Prandtl number)

A NPr

B NPr1/3

C NPr-1

D NPr-1/3

ANS:B - NPr1/3

For flow over a flat plate, the ratio of thermal boundary layer thickness xt​ to hydrodynamic boundary layer thickness x is given by the Prandtl number (Pr). Mathematically, it can be expressed as: xxt​​=NPr​ Where:

  • xt​ is the thermal boundary layer thickness,
  • x is the hydrodynamic boundary layer thickness, and
  • NPr is the Prandtl number.
So, the ratio of thermal boundary layer thickness to hydrodynamic boundary layer thickness is equal to the square root of the Prandtl number.