比焓与比熵定义及区别（Definition and difference of specific enthalpy and specific entropy）.doc

比焓与比熵定义及区别（Definition and difference of specific enthalpy and specific entropy） The engineering thermodynamics states that the value of the heat absorbed by the system is positive, and the value of the heat released by the system is negative. In the reversible process, the formula for calculating the heat exchange between the system and the outside world has the same form as the formula for the calculation of the work. For a micro unit reversible process, the quantity of heat exchanged between a unit mass and the outside can be expressed as Delta q=Tds In the formula, s is called the entropy ratio, and the unit is J/ (kg. K) or kJ/ (kg. K). The ratio entropy is defined as Ds= Delta q/T That is, in the infinitesimal reversible process, the increase of the specific entropy of the working substance is equal to the heat absorbed by the unit mass, the heat absorbed by the refrigerant, and the quotient obtained by the thermodynamic temperature. Like entropy S, same as volume V, it is the state parameter of working substance. Similar to the enthalpy definition; Entropy is a measure of the probability of a random thermal motion, that is, the degree of disorder or disorder of thermal motion, usually in terms of its amount of change, expressed in S Enthalpy is not energy. It has only the dimension of energy. It has no definite physical meaning. As in entropy, it is expressed in H Thermodynamic energy (U): the sum of energy in a system (average kinetic energy, rotational energy, vibrational energy, intermolecular potential energy, interatomic bond energy, electron kinetic energy, nucleus ion, inter nuclear energy, etc.). Consider all the factors involved in a reaction process as a system in which there is a thermodynamic energy above U1 and U2 after reaction. A condition in which the pressure of the system remains the same before and after the reaction (and even in the course of the reaction). There will be a change in volume of the system before and after the reaction. Part o