Heat Transfer interview questions

1. A.plot of heat flux against wall superheat through nucleate, transition and film regimes; the peak is the critical heat flux beyond which tube burnout occurs
2. B.conduction rate is proportional to area and to the negative temperature gradient, with thermal conductivity as the proportionality constant
3. C.black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴
4. D.outer radius (k/h for a cylinder) below which adding insulation to a small pipe increases heat loss because the outer area grows faster than resistance

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1. A.Critical radius of insulation
2. B.Overall heat transfer coefficient
3. C.Fourier's law
4. D.Boiling curve

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1. A.Fourier's law — plot of heat flux against wall superheat through nucleate, transition and film regimes; the peak is the critical heat flux beyond which tube burnout occurs
2. B.Fourier's law — outer radius (k/h for a cylinder) below which adding insulation to a small pipe increases heat loss because the outer area grows faster than resistance
3. C.Fourier's law — logarithmic mean of the two terminal temperature differences, the correct mean driving force for pure counter-current or co-current exchangers
4. D.Fourier's law — conduction rate is proportional to area and to the negative temperature gradient, with thermal conductivity as the proportionality constant

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1. A.reciprocal of the sum of inside film, wall, outside film and fouling resistances in series, used in Q = U·A·ΔT
2. B.plot of heat flux against wall superheat through nucleate, transition and film regimes; the peak is the critical heat flux beyond which tube burnout occurs
3. C.convective heat flux equals the film heat transfer coefficient times the temperature difference between surface and bulk fluid
4. D.black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴

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1. A.Fourier's law
2. B.Newton's law of cooling
3. C.Critical radius of insulation
4. D.Stefan-Boltzmann law

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1. A.Newton's law of cooling — plot of heat flux against wall superheat through nucleate, transition and film regimes; the peak is the critical heat flux beyond which tube burnout occurs
2. B.Newton's law of cooling — reciprocal of the sum of inside film, wall, outside film and fouling resistances in series, used in Q = U·A·ΔT
3. C.Newton's law of cooling — conduction rate is proportional to area and to the negative temperature gradient, with thermal conductivity as the proportionality constant
4. D.Newton's law of cooling — convective heat flux equals the film heat transfer coefficient times the temperature difference between surface and bulk fluid

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1. A.convective heat flux equals the film heat transfer coefficient times the temperature difference between surface and bulk fluid
2. B.logarithmic mean of the two terminal temperature differences, the correct mean driving force for pure counter-current or co-current exchangers
3. C.black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴
4. D.reciprocal of the sum of inside film, wall, outside film and fouling resistances in series, used in Q = U·A·ΔT

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1. A.Overall heat transfer coefficient
2. B.Dittus-Boelter correlation
3. C.Boiling curve
4. D.Stefan-Boltzmann law

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1. A.Stefan-Boltzmann law — reciprocal of the sum of inside film, wall, outside film and fouling resistances in series, used in Q = U·A·ΔT
2. B.Stefan-Boltzmann law — black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴
3. C.Stefan-Boltzmann law — outer radius (k/h for a cylinder) below which adding insulation to a small pipe increases heat loss because the outer area grows faster than resistance
4. D.Stefan-Boltzmann law — convective heat flux equals the film heat transfer coefficient times the temperature difference between surface and bulk fluid

Answer + AI explanation with Pro

1. A.outer radius (k/h for a cylinder) below which adding insulation to a small pipe increases heat loss because the outer area grows faster than resistance
2. B.plot of heat flux against wall superheat through nucleate, transition and film regimes; the peak is the critical heat flux beyond which tube burnout occurs
3. C.dimensionless ratio of convective to conductive heat transfer, hD/k, which convection correlations are written to predict
4. D.logarithmic mean of the two terminal temperature differences, the correct mean driving force for pure counter-current or co-current exchangers

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1. A.LMTD
2. B.Nusselt number
3. C.Dittus-Boelter correlation
4. D.Fourier's law

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1. A.Nusselt number — convective heat flux equals the film heat transfer coefficient times the temperature difference between surface and bulk fluid
2. B.Nusselt number — black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴
3. C.Nusselt number — dimensionless ratio of convective to conductive heat transfer, hD/k, which convection correlations are written to predict
4. D.Nusselt number — logarithmic mean of the two terminal temperature differences, the correct mean driving force for pure counter-current or co-current exchangers

Answer + AI explanation with Pro

1. A.turbulent pipe-flow relation Nu = 0.023 Re^0.8 Pr^n with n = 0.4 for heating and 0.3 for cooling of the fluid
2. B.black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴
3. C.dimensionless ratio of convective to conductive heat transfer, hD/k, which convection correlations are written to predict
4. D.conduction rate is proportional to area and to the negative temperature gradient, with thermal conductivity as the proportionality constant

Answer + AI explanation with Pro

1. A.Critical radius of insulation
2. B.Nusselt number
3. C.Dittus-Boelter correlation
4. D.Newton's law of cooling

Answer + AI explanation with Pro

1. A.Dittus-Boelter correlation — conduction rate is proportional to area and to the negative temperature gradient, with thermal conductivity as the proportionality constant
2. B.Dittus-Boelter correlation — turbulent pipe-flow relation Nu = 0.023 Re^0.8 Pr^n with n = 0.4 for heating and 0.3 for cooling of the fluid
3. C.Dittus-Boelter correlation — convective heat flux equals the film heat transfer coefficient times the temperature difference between surface and bulk fluid
4. D.Dittus-Boelter correlation — dimensionless ratio of convective to conductive heat transfer, hD/k, which convection correlations are written to predict

Answer + AI explanation with Pro

1. A.conduction rate is proportional to area and to the negative temperature gradient, with thermal conductivity as the proportionality constant
2. B.reciprocal of the sum of inside film, wall, outside film and fouling resistances in series, used in Q = U·A·ΔT
3. C.convective heat flux equals the film heat transfer coefficient times the temperature difference between surface and bulk fluid
4. D.black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴

Answer + AI explanation with Pro

1. A.Stefan-Boltzmann law
2. B.Critical radius of insulation
3. C.Nusselt number
4. D.Overall heat transfer coefficient

Answer + AI explanation with Pro

1. A.Overall heat transfer coefficient — dimensionless ratio of convective to conductive heat transfer, hD/k, which convection correlations are written to predict
2. B.Overall heat transfer coefficient — reciprocal of the sum of inside film, wall, outside film and fouling resistances in series, used in Q = U·A·ΔT
3. C.Overall heat transfer coefficient — convective heat flux equals the film heat transfer coefficient times the temperature difference between surface and bulk fluid
4. D.Overall heat transfer coefficient — logarithmic mean of the two terminal temperature differences, the correct mean driving force for pure counter-current or co-current exchangers

Answer + AI explanation with Pro

1. A.black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴
2. B.plot of heat flux against wall superheat through nucleate, transition and film regimes; the peak is the critical heat flux beyond which tube burnout occurs
3. C.logarithmic mean of the two terminal temperature differences, the correct mean driving force for pure counter-current or co-current exchangers
4. D.dimensionless ratio of convective to conductive heat transfer, hD/k, which convection correlations are written to predict

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1. A.Stefan-Boltzmann law
2. B.Critical radius of insulation
3. C.Dittus-Boelter correlation
4. D.LMTD

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1. A.LMTD — logarithmic mean of the two terminal temperature differences, the correct mean driving force for pure counter-current or co-current exchangers
2. B.LMTD — convective heat flux equals the film heat transfer coefficient times the temperature difference between surface and bulk fluid
3. C.LMTD — black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴
4. D.LMTD — turbulent pipe-flow relation Nu = 0.023 Re^0.8 Pr^n with n = 0.4 for heating and 0.3 for cooling of the fluid

Answer + AI explanation with Pro

1. A.turbulent pipe-flow relation Nu = 0.023 Re^0.8 Pr^n with n = 0.4 for heating and 0.3 for cooling of the fluid
2. B.convective heat flux equals the film heat transfer coefficient times the temperature difference between surface and bulk fluid
3. C.outer radius (k/h for a cylinder) below which adding insulation to a small pipe increases heat loss because the outer area grows faster than resistance
4. D.black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴

Answer + AI explanation with Pro

1. A.Newton's law of cooling
2. B.Nusselt number
3. C.Critical radius of insulation
4. D.Boiling curve

Answer + AI explanation with Pro

1. A.Critical radius of insulation — logarithmic mean of the two terminal temperature differences, the correct mean driving force for pure counter-current or co-current exchangers
2. B.Critical radius of insulation — outer radius (k/h for a cylinder) below which adding insulation to a small pipe increases heat loss because the outer area grows faster than resistance
3. C.Critical radius of insulation — reciprocal of the sum of inside film, wall, outside film and fouling resistances in series, used in Q = U·A·ΔT
4. D.Critical radius of insulation — plot of heat flux against wall superheat through nucleate, transition and film regimes; the peak is the critical heat flux beyond which tube burnout occurs

Answer + AI explanation with Pro

1. A.plot of heat flux against wall superheat through nucleate, transition and film regimes; the peak is the critical heat flux beyond which tube burnout occurs
2. B.turbulent pipe-flow relation Nu = 0.023 Re^0.8 Pr^n with n = 0.4 for heating and 0.3 for cooling of the fluid
3. C.reciprocal of the sum of inside film, wall, outside film and fouling resistances in series, used in Q = U·A·ΔT
4. D.conduction rate is proportional to area and to the negative temperature gradient, with thermal conductivity as the proportionality constant

Answer + AI explanation with Pro

1. A.Overall heat transfer coefficient
2. B.Boiling curve
3. C.LMTD
4. D.Dittus-Boelter correlation

Answer + AI explanation with Pro

1. A.Boiling curve — dimensionless ratio of convective to conductive heat transfer, hD/k, which convection correlations are written to predict
2. B.Boiling curve — turbulent pipe-flow relation Nu = 0.023 Re^0.8 Pr^n with n = 0.4 for heating and 0.3 for cooling of the fluid
3. C.Boiling curve — black-body emissive power is proportional to the fourth power of absolute temperature with constant 5.67 × 10⁻⁸ W/m²K⁴
4. D.Boiling curve — plot of heat flux against wall superheat through nucleate, transition and film regimes; the peak is the critical heat flux beyond which tube burnout occurs

Answer + AI explanation with Pro