2 Process of heat transfer Substantially the heat flow amounts to disorderly variation of internal energy With time The temperature difference takes place the heat transfer
2 Process of heat transfer Substantially, the heat flow amounts to disorderly variation of internal energy with time The temperature difference takes place the heat transfer
3 Applications of heat transfer The problem of determining the temperature distribution and the heat flow is of interest in many branches of science and technology or engineering) In power engineering heat exchangers, boilers condensers, burners nuclear reactor cores radiators In aerospace technology temp. and heat flow, high velocity ,weight, safety In heating and air-conditioning building structure, estimate insulation, prevent excessive heat losses In electronic and electrical engineering heat distribution heat stress, dissipation
3 Applications of heat transfer The problem of determining the temperature distribution and the heat flow is of interest in many branches of science and technology (or engineering). In power engineering heat exchangers, boilers condensers, burners, nuclear reactor cores, radiators In aerospace technology temp. and heat flow,high velocity,weight, safety In heating and air-conditioning building structure, estimate insulation, prevent excessive heat losses In electronic and electrical engineering heat distribution, heat stress, dissipation
4 Study method a Classical macroscopic study method macroscopic phenomenology method Phenomenon→ Abstract→ Mathematical description(mould)= Solution (Analysis Numerical, Experimental) a Building mould Mass, momentum or energy conservation law plus the mass, fluid viscous or heat conductive basic law = differential equation
4 Study method Classical macroscopic study method (macroscopic phenomenology Method) Phenomenon ⇒ Abstract ⇒ Mathematical description(mould) ⇒ Solution (Analysis, Numerical, Experimental) Building mould Mass, momentum or energy conservation law plus the mass,fluid viscous or heat conductive basic law ⇒differential equation
5 Learning heat transfer a Have a profound grasp of the essential of heat transfer construction, research method, general regularity, mathematical and physical moulds a Know well the basic definitions, concepts, laws calculation methods Normal learning listen to teaching, write note discuss questions accomplish fixed exercises make experiments
5 Learning heat transfer Have a profound grasp of the essential of heat transfer construction, research method, general regularity, mathematical and physical moulds. Know well the basic definitions, concepts, laws, calculation methods. Normal learning listen to teaching, write note, discuss questions, accomplish fixed exercises, make experiments
1-1 Three Basic Modes of heat Transfer a three modes: conduction the aid of the motion of the microscopic particles convection the aid of the motion of the macroscopic fluids Radiation the aid of the propagation of electromagnetic waves The temperature field is controlled by combined effects, it is not possible to isolate entirely one mode. For simplicity, one mode can consider separately Give a brief qualitative description of the three modes
1-1 Three Basic Modes of heat Transfer Three modes: conduction the aid of the motion of the microscopic particles convection the aid of the motion of the macroscopic fluids Radiation the aid of the propagation of electromagnetic waves The temperature field is controlled by combined effects, it is not possible to isolate entirely one mode. For simplicity, one mode can consider separately. Give a brief qualitative description of the three modes