第一些定义:* * * *潜热是离开或进入系统的热过程中系统的温度保持不变。相变是主要例子潜热叶子(放热)或进入(吸热)系统。冰融化(吸热)和水(放热)在恒定温度下结冰。* * * *显热是热,进入或退出系统时,系统的温度变化。加热或冷却水涉及显热的情况下。所有热流两个系统之间需要一个系统之间的温差。* * * *对流运动是两个系统之间的热流的质量。另外两个热量流* *传导辐射* * * *和* *。现在的问题:在相变过程中,系统的温度保持不变。得到或者失去的热量称为潜热。 To vaporize a liquid, we must supply heat. Hence vaporization is endothermic (heat enters the system). To get the heat into the system, we must set the surroundings at a hotter temperature. Otherwise the heat will not flow. The process by which the heat flows can be any one of the three modes. We can set a pot of water in a pan on an electric heater and realize conduction from the burner to the pan to the water. We can set use a hair dryer to blow hot air over the pot and realize (forced) convection from the air to the pan. Finally, we can set the pot a small distance above the glowing electric burner and realize radiation from the electric burner to the pot. By contrast, consider the case of a day where the outside temperature is below freezing and the air is still. A duck pond in the yard is not frozen over. Clearly, it’s water temperature is above freezing. Should we jump in the duck pond to warm up? Of course not! The convection coefficient of water is higher than air. The water would pull heat from us by convection, and our body temperature would drop faster than when we would stay standing in the still air. The heat that flows out of our body as our body temperature drops is sensible heat.