# Heat-Transfer viva questions

• What is heat transfer, and how is it defined?
• What are the three modes of heat transfer, and how are they different?
• How is heat transferred by conduction, and what factors affect its rate?
• What is thermal conductivity, and how is it measured?
• How does the thermal conductivity of materials affect their heat transfer rates?
• What is convection, and how does it differ from conduction?
• How does the rate of convection heat transfer depend on the fluid properties and the geometry of the system?
• What is radiation, and how does it differ from conduction and convection?
• What factors affect the rate of radiative heat transfer?
• How do materials affect the absorption and emission of radiation?
• What is the Stefan-Boltzmann law, and how is it used to calculate radiative heat transfer?
• How do engineers use heat transfer principles to design and optimize systems, such as heat exchangers and thermal insulation?
• How is heat transfer related to the second law of thermodynamics?
• What is Fourier’s law, and how is it used to calculate conduction heat transfer?
• How does the geometry of a system affect conduction heat transfer?
• What is the heat equation, and how is it used to model heat transfer in different materials?
• What is thermal resistance, and how is it used in heat transfer calculations?
• How is the concept of thermal boundary resistance used to model heat transfer at interfaces?
• What is the difference between steady-state and transient heat transfer?
• What is the lumped capacitance method, and when is it used to solve transient heat transfer problems?
• What is the Biot number, and how is it used to determine the applicability of the lumped capacitance method?
• What is the heat transfer coefficient, and how is it related to convection heat transfer?
• What is Nusselt number, and how is it used to characterize convective heat transfer?
• What is Prandtl number, and how is it used to characterize fluid properties in convection heat transfer?
• What is Reynolds number, and how is it used to determine the flow regime in convective heat transfer?
• What is laminar flow, and how does it differ from turbulent flow?
• What is boundary layer, and how does it affect convective heat transfer?
• What is forced convection, and how does it differ from natural convection?
• What is the difference between external and internal flow in convective heat transfer?
• What is film coefficient, and how is it used in convective heat transfer calculations?
• What is the difference between parallel and counter flow in heat exchangers?
• What is fouling, and how does it affect heat transfer in heat exchangers?
• What is the effectiveness-NTU method, and how is it used to design heat exchangers?
• What is a fin, and how does it enhance heat transfer?
• What is a heat sink, and how is it designed to dissipate heat?
• What is a heat pipe, and how does it work to transfer heat?
• What is thermal insulation, and how does it reduce heat transfer?
• What is thermal resistance network, and how is it used to analyze heat transfer in complex systems?
• What is the difference between conductive and radiative heat transfer in thermal insulation?
• What is the difference between steady-state and transient heat transfer in thermal insulation?
• What is the difference between thermal conductivity and thermal resistivity?
• What is the difference between thermal diffusivity and thermal conductivity?
• What is the difference between specific heat and heat capacity?
• What is the difference between enthalpy and internal energy?
• What is the difference between sensible and latent heat?
• What is the difference between emissivity and absorptivity?
• What is the difference between blackbody and graybody radiation?
• What is Kirchhoff’s law, and how is it used to relate emissivity and absorptivity?
• What is Wien’s law, and how is it used to calculate the peak wavelength of blackbody radiation?
• What is Planck’s law, and how is it used to calculate the spectral intensity of blackbody radiation?
• What is Stefan-Boltzmann constant, and how is it used in radiative heat transfer calculations?
• What is the difference between opaque and transparent materials in radiative heat transfer?
• What is the difference between reflectance and transmittance in radiative heat transfer?
• What is the heat transfer coefficient for radiation, and how is it calculated?
• What is the view factor, and how is it used in radiative heat transfer calculations?
• What is the difference between selective and non-selective surfaces in radiative heat transfer?
• What is the difference between direct and diffuse radiation?
• What is the greenhouse effect, and how does it affect radiative heat transfer in the atmosphere?
• What is the difference between local and average heat transfer coefficients?
• What is the Reynolds analogy, and how is it used to relate convection and conduction heat transfer?
• What is the difference between evaporation and condensation heat transfer?
• What is the difference between single-phase and two-phase flow in heat transfer?
• What is the difference between subcooled boiling and nucleate boiling?
• What is the difference between pool boiling and forced convection boiling?
• What is the difference between film boiling and critical heat flux?
• What is the Leidenfrost effect, and how does it affect boiling heat transfer?
• What is the difference between convective and radiative heat transfer in combustion?
• What is the difference between laminar and turbulent flames, and how does it affect heat transfer?
• What is the difference between premixed and non-premixed flames, and how does it affect heat transfer?
• What is the difference between flame temperature and adiabatic flame temperature?
• What is the difference between convective and radiative heat transfer in furnaces?
• What is the difference between regenerative and recuperative heat exchangers?
• What is the difference between cross-flow and counter-flow heat exchangers?
• What is the difference between shell-and-tube and plate heat exchangers?
• What is the difference between thermal and hydraulic efficiency in heat exchangers?
• What is the difference between laminar and turbulent flow in porous media heat transfer?
• What is the difference between effective and apparent thermal conductivity in porous media heat transfer?
• What is the difference between steady-state and transient heat transfer in porous media?
• What is the difference between convective and conductive heat transfer in soil?
• What is geothermal heat transfer, and how is it used for heating and cooling?
• What is the difference between steady-state and transient heat transfer in geothermal systems?
• What is the difference between open and closed loop geothermal systems?
• What is the difference between horizontal and vertical ground heat exchangers?
• What is the difference between heat transfer in air and water, and how does it affect heat exchanger design?
• What is the difference between natural and forced convection in air, and how does it affect heat transfer?
• What is the difference between radiant and convective heat transfer in air, and how does it affect heating and cooling systems?
• What is the difference between sensible and latent cooling, and how is it used in air conditioning systems?
• What is the difference between DX and chilled water cooling systems in air conditioning?
• What is the difference between air-cooled and water-cooled chillers in air conditioning?
• What is the difference between single-stage and multi-stage cooling systems in air conditioning?
• What is the difference between cooling and dehumidification in air conditioning?
• What is the difference between air-to-air and air-to-water heat pumps, and how do they work?
• What is the difference between COP and EER in heat pump efficiency?
• What is the difference between ground-source and air-source heat pumps, and how do they compare in efficiency?
• What is the difference between thermal conductivity and thermal diffusivity?
• What is the difference between a steady-state and transient heat conduction problem?
• What is the definition of a Biot number, and what is its significance?
• What is the definition of a Fourier number, and what is its significance?
• What is the definition of a Nusselt number, and what is its significance?
• What is the definition of a Peclet number, and what is its significance?
• What is the definition of a Prandtl number, and what is its significance?
• What is the definition of a Reynolds number, and what is its significance?
• What is the definition of a Schmidt number, and what is its significance?
• What is the definition of a Stanton number, and what is its significance?
• What is the definition of a Sherwood number, and what is its significance?
• What is the definition of a Grashof number, and what is its significance?
• What is the definition of a Rayleigh number, and what is its significance?
• What is the definition of a Strouhal number, and what is its significance?
• What is the definition of a Mach number, and what is its significance?
• What is the definition of a Weber number, and what is its significance?
• What is the definition of a Bond number, and what is its significance?
• What is the definition of a Froude number, and what is its significance?
• What is the definition of a Lewis number, and what is its significance?
• What is the definition of a Stanton number, and what is its significance?
• What is the difference between conduction, convection, and radiation heat transfer?
• What are the major factors affecting convective heat transfer in fluids?
• What are the major factors affecting convective heat transfer in gases?
• What are the major factors affecting convective heat transfer in solids?
• What is the difference between internal and external flow heat transfer?
• What is the difference between forced and natural convection heat transfer?
• What is the difference between boundary layer and fully developed flow heat transfer?
• What is the difference between a thermal boundary layer and a velocity boundary layer?
• What is the difference between heat transfer in laminar and turbulent flow?
• What is the difference between a boundary condition and an initial condition in heat transfer?
• What is the difference between an insulated and an adiabatic boundary condition in heat transfer?
• What is the difference between a constant wall temperature and a constant heat flux boundary condition in heat transfer?
• What is the difference between a heat exchanger and a heat sink?
• What is the difference between a counter-flow and a parallel-flow heat exchanger?
• What is the difference between a co-current and a cross-current heat exchanger?
• What is the difference between a single-pass and a multi-pass heat exchanger?
• What is the difference between a compact and a non-compact heat exchanger?
• What is the difference between a finned and a plain tube heat exchanger?
• What is the difference between a compact and a non-compact heat exchanger?
• What is the difference between a shell-and-tube and a plate heat exchanger?
• What is the difference between a condenser and an evaporator in a refrigeration cycle?
• What is the difference between a compressor and a condenser in a refrigeration cycle?
• What is the difference between a thermosyphon and a heat pipe?
• What is the difference between a steady-state and unsteady-state heat transfer problem?
• What is the difference between a boundary layer and a wake in fluid flow?
• What is the difference between heat capacity and specific heat?
• What is the difference between a laminar and a turbulent boundary layer?
• What is the difference between heat flux and heat transfer rate?
• What is the difference between an ideal and a real heat exchanger?
• What is the difference between a regenerator and a recuperator heat exchanger?
• What is the difference between a cross-flow and a counter-flow heat exchanger?
• What is the difference between a dry and a wet cooling tower?
• What is the difference between a simple and a compound tube heat exchanger?
• What is the difference between a shell-and-tube and a plate heat exchanger?
• What is the difference between a convective and a radiative heat transfer coefficient?
• What is the difference between a transient and a periodic heat transfer problem?
• What is the difference between a conduction and a convection boundary condition?
• What is the difference between a longitudinal and a transverse fin in a heat exchanger?
• What is the difference between a logarithmic and an arithmetic mean temperature difference in heat exchanger design?
• What is the difference between a direct and an indirect contact heat exchanger?
• What is the difference between a non-reheat and a reheat steam power plant?
• What is the difference between a counter-flow and a parallel-flow heat exchanger?
• What is the difference between a natural and a forced convection heat transfer problem?
• What is the difference between an isothermal and an adiabatic process in thermodynamics?
• What is the difference between a thermocouple and a resistance thermometer in temperature measurement?
• What is the difference between a steady and a fluctuating fluid flow?
• What is the difference between a laminar and a turbulent flow regime in fluid dynamics?
• What is the difference between a conduction and a convection heat transfer mode?
• What is the difference between a stationary and a moving boundary condition in heat transfer?
• What is the difference between a pure substance and a mixture in thermodynamics?
• What is the difference between an ideal gas and a real gas in thermodynamics?
• What is the difference between a compressible and an incompressible fluid in fluid mechanics?
• What is the difference between a pressure vessel and a heat exchanger in engineering design?
• What is the difference between a heat sink and a heat source in thermal engineering?
• What is the difference between a steady and an unsteady flow in fluid dynamics?
• What is the difference between a flat plate and a cylindrical surface in heat transfer analysis?
• What is the difference between a transient and a steady-state temperature distribution in a solid?
• What is the difference between a thermal and a mechanical boundary condition in a heat transfer problem?
• What is the difference between a wet and a dry bulb thermometer in temperature measurement?
• What is the difference between a mixed and a forced convection heat transfer problem?
• What is the difference between a convective and a radiative boundary condition in heat transfer analysis?
• What is the difference between a heat flux and a heat transfer coefficient in heat transfer analysis?
• What is the difference between a first and a second law of thermodynamics in thermodynamics?
• What is the difference between an isobaric and an isochoric process in thermodynamics?