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Heat-transfer Questions Set 28:

Quiz Mode

Thermal conductivity is lower for:

wood

air

steam at 1 bar

water at 100 degrees Celsius

Solution:

What is the power per tonne of refrigeration?

3.5 x C.O.P.

C.O.P/3.5

3.5/C.O.P.

3 * 3.5/C.O.P.

Solution:

For a prescribed wavelength, how much energy does a black body radiate at its own temperature?

Maximum

50%

Minimum

20%

Solution:

Which dimensionless number represents the ratio of internal (conduction) resistance to the surface (convective) resistance?

Nusselt number

Fourier number

Stanton number

Biot number

Solution:

What does the area under the spectral hemispherical emissive power (E_λ) vs. wavelength (λ) graph represent?

Total Intensity

Spectral hemispherical intensity

Total hemispherical emissive power

None of the above

Solution:

A 3.2 mm diameter stainless steel wire, 30 cm long has a resistance of 0.0261 ohms and carries a current of 383.14 amperes. Calculate the heat generated.

96.55 W/m^3.

15.89 W/m^3.

96.55 × 10^8 W/m^3.

15.89 × 10^8 W/m^3.

Solution:

If the convective heat transfer coefficient, specific heat capacity (Cp), and the volume are given, which additional parameter is required to calculate the Stanton number?

Area

Temperature change

Characteristic length

Density

Solution:

An oil cooler in a high-performance engine has an outside surface area of 0.12 m² and a surface temperature of 65°C. At any intermediate time, air moves over the surface of the cooler at a temperature of 30°C and gives rise to a surface coefficient of 45.4 W/m²·K. Find the heat transfer rate.

238.43 W

190.68 W

543.67 W

675.98 W

Solution:

The operating temperature of a cold storage is -3°C. The heat leakage from the surrounding is 40 kW for the ambient temperature of 40°C. The actual C.O.P. of the refrigeration plant used is one-fourth that of the ideal plant working between the same temperatures. What is the power required to drive the plant?

20 kW

19.4 kW

19.6 kW

21 kW

Solution:

For a heat exchanger, ΔT_max is the maximum temperature difference and ΔT_min is the minimum temperature difference between the two fluids. LMTD is the log mean temperature difference. C_min and C_max are the minimum and the maximum heat capacity rates. What is the maximum possible heat transfer (Q_max) between the two fluids?

C_min LMTD

C_min ΔT_max

C_max ΔT_max

C_max ΔT_min

Heat-transfer Questions Set 28:

Thermal conductivity is lower for:

Solution:

What is the power per tonne of refrigeration?

Solution:

For a prescribed wavelength, how much energy does a black body radiate at its own temperature?

Solution:

Which dimensionless number represents the ratio of internal (conduction) resistance to the surface (convective) resistance?

Solution:

What does the area under the spectral hemispherical emissive power (E_λ) vs. wavelength (λ) graph represent?

Solution:

A 3.2 mm diameter stainless steel wire, 30 cm long has a resistance of 0.0261 ohms and carries a current of 383.14 amperes. Calculate the heat generated.

Solution:

If the convective heat transfer coefficient, specific heat capacity (Cp), and the volume are given, which additional parameter is required to calculate the Stanton number?

Solution:

An oil cooler in a high-performance engine has an outside surface area of 0.12 m² and a surface temperature of 65°C. At any intermediate time, air moves over the surface of the cooler at a temperature of 30°C and gives rise to a surface coefficient of 45.4 W/m²·K. Find the heat transfer rate.

Solution:

Solution:

Solution:

Related Question Sets:

Related Topics:

Heat-transfer Questions Set 28:

Thermal conductivity is lower for:

Solution:

What is the power per tonne of refrigeration?

Solution:

For a prescribed wavelength, how much energy does a black body radiate at its own temperature?

Solution:

Which dimensionless number represents the ratio of internal (conduction) resistance to the surface (convective) resistance?

Solution:

What does the area under the spectral hemispherical emissive power (Eλ) vs. wavelength (λ) graph represent?

Solution:

A 3.2 mm diameter stainless steel wire, 30 cm long has a resistance of 0.0261 ohms and carries a current of 383.14 amperes. Calculate the heat generated.

Solution:

If the convective heat transfer coefficient, specific heat capacity (Cp), and the volume are given, which additional parameter is required to calculate the Stanton number?

Solution:

An oil cooler in a high-performance engine has an outside surface area of 0.12 m² and a surface temperature of 65°C. At any intermediate time, air moves over the surface of the cooler at a temperature of 30°C and gives rise to a surface coefficient of 45.4 W/m²·K. Find the heat transfer rate.

Solution:

Solution:

Solution:

Related Question Sets:

Related Topics:

What does the area under the spectral hemispherical emissive power (E_λ) vs. wavelength (λ) graph represent?