contestada

In a gas turbine, air (kinematic viscosity of 1x104-5 m 2/s) flows over a 2 cm long turbine blade at 100 m/s. How long should the blade be in my lab's wind tunnel (air, kinematic viscosity of 1.5x10A-5 mA2/s, velocity of 10 m/s), to match the Reynolds number of the gas turbine? a)-2cm b)-30cm c)-0.3cm

Respuesta :

Answer:

30 cm

Explanation:

For  Reynold's number similarity between model and prototype we should  have

[tex]R_{e}  _{model} =R_{_{e prototype}}  \\\\\frac{V_{model} L_{model} }{kinematic viscosity in model} =\frac{V_{proto}L_{proto}  }{kinematic viscosity in prototype}[/tex]

Given L(prototype)= 2cm

V(prototype) = 100m/s

V(model) = 10m/s

 Thus applying values in the above equation we get

[tex]\frac{100m/s^{} X2cm^{}  }{1X10^{-5}m^{2}/s  } =\frac{L_{M}X10m/s }{1.5X10^{-5}m^{2}/s }[/tex]

Solving for Lmodel we get Lm = 30cm