Prandtl number for most of dry gases is about________________?

Related Mcqs:

1. In a laboratory test run, the rate of drying was found to be 0.5 x 10-3 kg/m2.s, when the moisture content reduced from 0.4 to 0.1 on dry basis. The critical moisture content of the material is 0.08 on a dry basis. A tray dryer is used to dry 100 kg (dry basis) of the same material under identical conditions. The surface area of the material is 0.04 m2/kg of dry solid. The time required (in seconds) to reduce the moisture content of the solids from 0.3 to 0.2 (dry basis) is______________________?

   A. 2000
   B. 4000
   C. 5000
   D. 6000

2. 200 kg of solids (on dry basis) is subjected to a drying process for a period of 5000 seconds. The drying occurs in the constant rate period with the drying rate as, Nc = 0.5 × 10-3 kg/m2.s. The initial moisture content of the solid is 0.2 kg moisture/kg dry solid. The interfacial area available for drying is 4 m2/1000 kg of dry solid. The moisture content at the end of the drying period is (in kg moisture/kg dry solid)?

   A. 0.5
   B. 0.05
   C. 0.1
   D. 0.15

3. Prandtl and Reynold’s analogies are identical for Prandtl number value of__________________?

   A. 0
   B. 0.5
   C. 1
   D. 5

4. Prandtl and Reynolds analogy are same, when Prandtl number is____________________?

   A. 0.5
   B. 1
   C. > 2
   D. 1.5

5. Heat transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible, if the value of Prandtl number is_______________?

   A. 0.2
   B. 0.4
   C. 0.6
   D. 0.8

6. For _______________ Prandtl number values, the heat conduction will be negligible in the buffer zone?

   A. Extremely low
   B. Low
   C. High
   D. No

7. Nusselt number is a function of Prandtl number and ______________ number of fluid in natural convection heat transfer?

   A. Grashoff
   B. Biot
   C. Stanton
   D. Reynolds

8. Colburn analogy is applicable for the value of Prandtl number from_________________?

   A. 0.001 to 1
   B. 0.6 to 120
   C. 0.5 to 5
   D. 120 to 400

9. Conduction occurs in the buffer zone for a fluid flowing through a heated pipe, only when Prandtl number is________________?

   A. 0.1
   B. > 1
   C. < 1
   D. 1

10. If Prandtl number is greater than the Schmidt number, then the____________________?

    A. Thermal boundary layer lies inside the concentration boundary layer
    B. Concentration boundary layer lies inside the thermal boundary layer
    C. Thermal & concentration boundary layers are of equal thickness
    D. Hydrodynamic (i.e., momentum) boundary layer is thicker than the other two