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空调房间的送风与回风之间存在温差,并因此也存在着密度差。密度差产生重力。在垂直射流的情况下,重力的作用及其与射流所具有的惯性力的关系是显而易见的。可区分为两种情况,这两种情况又分为两种不同的气流方向,见图1。气流方向可以由上向下,也可以由下向上。在情况1A中,冷射流降入温暖的房间中,存在冷风突降的危险。在房间中没有温度梯度的情况下,射流速度总是比等温射流时为大。在2A情况下,热空气由下向上流经冷的房间。在1B情况下,热空气由上向下流经房间。由于热浮升力与射流的惯性力相抵制,沿气流方向向下,射流速度可能变为零。这时,射流改变方向。在2B情况下,
There is a temperature difference between the supply air and return air in the air-conditioned room, and therefore there is also a difference in density. The difference in density produces gravity. In the case of vertical jets, the role of gravity and its relationship to the inertial force of the jet is obvious. Can be divided into two cases, these two cases are divided into two different air flow directions, see Figure 1. The direction of air flow can be from top to bottom or from bottom to top. In case 1A, cold jets are dropped into a warm room, and there is a danger of cold air dips. In the absence of a temperature gradient in the room, the jet velocity is always greater than that of an isothermal jet. In the case of 2A, hot air flows from the bottom up through the cold room. In the case of 1B, hot air flows up and down through the room. Because the buoyant lift force resists the inertial force of the jet, the jet velocity may go down to zero along the direction of the airflow. At this point, the jet changes direction. In case of 2B,