the oscillations of the velocity of the flows inside the tower are almost of the same character. In this connection it
is necessary to pay attention to the turbulent character of temperature fields when conducting the corresponding
investigations in actual towers.
The dependence of the temperature drop of the vapor-air mixture above the water distributor AT(0) on
the dimensionless complex R obtained after the processing of experimental data is presented in Fig. 4. Here, AT(0)
= T(0) - Ta, T(0) is the air temperature above the water distributor (in our case at z = 0). The complex R is
described by the following ratio:
Qw Cw ATw (6)
R-
Qa Ca Ta '
where Cw and Ca is the specific heat of water and air, respectively.
As shown below, such a form of expression (6) follows from the law of energy conservation. From Fig. 4
it is seen that there is virtually a linear dependence between the parameter R and air heating above the water
distributor.
Figure 5 presents the dependence of the thermal efficiency of the tower [1 ], defined as
r] = ATw/ ATlim , (7)
on the ratio of the mass flow rates of water Qw and air Qa. The air flow rate was determined experimentally from
the vertical flow velocity w averaged over the model outlet section. From Fig. 5 it is seen thai with flow swirling the
operating efficiency of the tower increases (curve 2 and points 3 in Fig. 5). This effect becomes stronger at higher
ratios between the flow rates of water and air. The experimental data on the efficiency of the tower obtained on
the laboratory model are described well by formula (4) at A = 3 in the conventional operating mode.
Special attention should be paid to the operation of the tower in the periodic (pulsating) mode of supply of
cooled water. At a certain frequency of oscillations associated with characteristic scales of the processes of transfer摘要:我们通过空气动力学方法从实验讲究中得到循环水在冷却塔中的蒸发冷却过程。关键词:冷却塔;空气动力学;冷却塔实验室模型1简介
烟囱型蒸发式冷却塔,广泛应用于大热核电站的冷却循环水,使附近的工厂产生重大影响的经济效益和生态状况。塔中水的冷却,取决于许多因素,包括外部冷空气气流进入塔、塔下部的风荷载和外部气流与温暖水蒸汽混合的影响。我们知道尝试用空气动力来修改现有版本塔的设计以达到提高效率的目的。
为了彻底了解在塔中发生的过程和进行主要的气动热过程的定量研究,本文作者开发了一个烟囱型蒸发式冷却塔实验室模型。在这项工作中,我们提出了从设计实验室装置上获得基本的调查结果。
在冷却塔中,温水和冷空气的相互作用导致加热水蒸汽 - 空气混合物,主要是因为出现温循环水蒸气再冷凝的蒸发结果。在塔内的阿基米德力生成自由对流的含有微米水珠的温暖的蒸气 - 空气混合物。这个气流的结构和强度在很大程度上决定,在这样的安装的过程中蒸发冷却的效率。对于大型现代化塔的高度H和基座直径D是相对称的(H/D≈1);因此,在底部附近摄入的空气和上半部分的逃出(占风速)的条件下,在塔里面的空气动力学过程产生重大影响。反过来,气动过程中水蒸发处理上有一个在非常显著的影响。
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