热水采暖系统重力循环,或称自然循环,其循环压力的计算方法虽然不是复杂的问题,却是个重要的原理问题。一、重力循环的原理:在考虑管道散热所产生的循环压力时,往往会认为管道内的循环水由下向上流动时会产生负循环压力,也就是阻碍正常循环的压力。当然,散热器的散热也是一样的道理。例如,从锅炉出来的总立管中的水就是由下向上流动的,这条立管的散热似乎会产生负值的循环压力。苏联基兴著《暖气工程》是这样写的:“但并不是所有管段内水的冷却都会使水头增加。在水沿着输管向上流动时冷却会使水头降低。假如水的冷 The gravity cycle of hot water heating system, or natural circulation, is not an important problem, but it is an important principle problem. First, the principle of gravity cycle: In considering the cyclic pressure generated by the cooling pipe, it is often thought that the circulating water in the pipe will flow from the bottom up and it will produce a negative cycle pressure, which is the pressure that hinders the normal cycle. Of course, the radiator heat dissipation is the same reason. For example, the water in the main riser coming out of the boiler flows from bottom to top. The heat dissipation of this riser seems to generate negative cyclic pressure. According to the Soviet Union’s Radiance Heating Project, "Not all the cooling of the water in the segment will increase the head. Cooling will reduce the head when the water flows up the trough. If the water is cold