Chemical Heat Transfer

Which of the following is unimportant in forced convection ?

Byadmin March 3, 2019August 24, 2021

Which of the following is unimportant in forced convection ?

A. Reynolds number
B. Prandtl number
C. Grashoff number
D. None of these

Chemical Heat Transfer

The Dittus-Boelter equation for convective heat transfer [(i.e. h = 0.023 (K/D) (Re)0.8 (Pr)0.4] cannot be used for________________?

The Dittus-Boelter equation for convective heat transfer [(i.e. h = 0.023 (K/D) (Re)0.8 (Pr)0.4] cannot be used for________________?

A. Low Reynold’s number
B. Very low Grashoff number
C. Molten metals
D. All A., B. and C.

Read More The Dittus-Boelter equation for convective heat transfer [(i.e. h = 0.023 (K/D) (Re)0.8 (Pr)0.4] cannot be used for________________?
Chemical Heat Transfer

A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________?

A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________?

A. t = 283 s
B. t = 356 s
C. t = 400 s
D. t = 800 s

Read More A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________?
Chemical Heat Transfer

Boiling point elevation of an ideal solution_______________?

Boiling point elevation of an ideal solution_______________?

A. Increases rapidly with temperature rise
B. Decreases rapidly with temperature rise
C. In independent of pressure
D. Both B. and C.

Read More Boiling point elevation of an ideal solution_______________?
Chemical Heat Transfer

The equivalent diameter for the annulus of a double pipe heat exchanger, whose inner pipe has fins on the outside is ______________ compared to the same size pipes without fins?

The equivalent diameter for the annulus of a double pipe heat exchanger, whose inner pipe has fins on the outside is ______________ compared to the same size pipes without fins?

A. More
B. Less
C. Same
D. Unpredictable

Read More The equivalent diameter for the annulus of a double pipe heat exchanger, whose inner pipe has fins on the outside is ______________ compared to the same size pipes without fins?
Chemical Heat Transfer

The wavelength at which the maximum monochromatic emissive power occurs for a black body, is (where, T = absolute temperature of the black body)?

The wavelength at which the maximum monochromatic emissive power occurs for a black body, is (where, T = absolute temperature of the black body)?

A. αT
B. α × 1/T
C. α T4
D. Independent of T

Read More The wavelength at which the maximum monochromatic emissive power occurs for a black body, is (where, T = absolute temperature of the black body)?
Chemical Heat Transfer

Which of the following has the highest thermal conductivity ?

Which of the following has the highest thermal conductivity ?

A. Brick
B. Air
C. Water
D. Silver

Read More Which of the following has the highest thermal conductivity ?

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