GE PRG-MODEM 调制调解器

热力学循环是指热力学系统在一系列状态变化后恢复 到原始状态的整个过程。热循环分为正向循环和反向循环。将热能转化为机械功的循环称为正向循环;机械功转化为热

量的循环称为反向循环。通过改变工作介质热状态的过程，可以将热能转化为机械能做功，一般必须通过 工作介质的膨胀过程来完成功，但任何热膨胀过程都不能一直持续做功。这是因为工作介质的状态将不适合进一步扩 展工作,而任何热工设备的尺寸都是有限的。例如，当通过恒温膨胀或绝热膨胀完成工作时，工作介质的压力将降低到无法完成工作的水平,诅工作介质的体积V将增加到设备尺寸无法允许的程度。-个典型的例子是密封在气瓶中的一定质量的气体。当它膨胀并起作用时，压力将继续减小，体积将继续增加。这种膨胀过程可能是由于压力下降过低而无法继续做功,或者由于气缸尺寸的限制，体积不能无限增加。

Thermodynamic cycle refers to the whole process of Thermodynamic system recovering to the original state after a series of state changes. The thermal cycle is divided into forward cycle and reverse cycle. The cycle of converting thermal energy into mechanical work is called a forward cycle; Conversion of mechanical work into heat

The cycle of quantity is called a reverse cycle. By changing the thermal state of the working medium, thermal energy can be converted into mechanical energy to do work. Generally, success must be achieved through the expansion process of the working medium, but any thermal expansion process cannot continue to do work. This is because the state of the working medium will not be suitable for further expansion of work, and the size of any thermal equipment is limited. For example, when work is completed through constant temperature expansion or adiabatic expansion, the pressure of the working medium will decrease to a level where it is impossible to complete the work, and the volume V of the working medium will increase to a degree that the equipment size cannot allow- A typical example is a certain mass of gas sealed in a gas cylinder. As it expands and functions, the pressure will continue to decrease and the volume will continue to increase. This expansion process may be due to a pressure drop that is too low to continue working, or due to cylinder size limitations, the volume cannot increase infinitely.