热风供暖送风方式对室外冷风作用范围的影响研究

发布时间：2019-06-19 02:48

【摘要】：人流量较大的公共场所不可避免的存在外门频繁开启的现象,在供暖季节必然导致室外冷风侵入室内。侵入室内的冷风受负浮力作用下沉后沿着地面扩散,使得人员工作区的温度降低。在过去二十多年里,碰撞射流的原理被逐渐运用到空气调节和通风领域,并发展成为一种新的通风方式——碰撞射流通风。该通风方式被认为是同时具备置换通风和混合通风的优点。从原理上考虑,碰撞射流通风系统将送风气流直接送到近地面,可以减小室外侵入的冷风对室内热环境的影响。本文针对供暖房间有明显室外冷风侵入时,在不同的送风参数下实测研究了碰撞射流通风和混合通风的供暖效果。结果表明,在两种送风方式下,供暖房间近地面的温度都因为室外冷风侵入而明显下降,温度分层现象较为明显,但是碰撞射流通风热风供暖房间的受影响范围远小于混合通风房间。对于混合通风和碰撞射流通风,提高送风温度均不能减小冷风对房间热环境的影响,反而增大房间的温度梯度,降低房间对供暖能量的利用率。尽管提高送风速度可以减小混合通风热风供暖房间的温度梯度,并缩小冷风对房间热环境的影响范围,但依然没有较低送风速度的碰撞射流通风热风供暖效果好。此外,碰撞射流通风的送风口高度影响热气流与冷气流的混合程度。因此本文针对不同的送风口高度,研究了碰撞射流通风热风供暖房间的温度和速度分布特征。结果表明,仅当送风速度较低时,降低送风口高度使得房间近地面处温度升高,缩小室外侵入冷风的作用范围。降低送风口高度虽然可以增大房间对供暖能量的利用率,减小近地面以上空间气流速度,但是增大了近地面处的气流速度;因为近地面处温度较高,可以弥补由于速度过大导致吹风感过大的不足,所以不会因为吹风感引起人员的不舒适。
[Abstract]:The phenomenon of frequent opening of the outer door is inevitable in the public places with large flow of people, which will inevitably lead to the invasion of outdoor cold air into the room during the heating season. The cold wind invading the room is diffused along the ground after sinking under the action of negative buoyancy, which reduces the temperature of the personnel working area. In the past two decades, the principle of collision jet has been gradually applied to the field of air conditioning and ventilation, and has developed into a new ventilation mode-collision jet ventilation. This ventilation method is considered to have the advantages of both displacement ventilation and mixed ventilation. In principle, the impact jet ventilation system can directly send the air supply to the near ground, which can reduce the influence of outdoor invasion of cold air on the indoor thermal environment. In this paper, the heating effect of collision jet ventilation and mixed ventilation is studied under different air supply parameters when there is obvious outdoor cold air invasion in heating room. The results show that under the two air supply modes, the temperature near the ground of the heating room decreases obviously because of the invasion of outdoor cold air, and the temperature stratification phenomenon is more obvious, but the affected range of the collision jet air hot air heating room is much smaller than that of the mixed ventilation room. For mixed ventilation and collision jet ventilation, increasing the air supply temperature can not reduce the influence of cold air on the thermal environment of the room, but increase the temperature gradient of the room and reduce the utilization rate of heating energy in the room. Although increasing the air supply speed can reduce the temperature gradient of mixed ventilation hot air heating room and reduce the influence range of cold air on the thermal environment of the room, there is still no better heating effect of collision jet air hot air with low air supply speed. In addition, the height of the air outlet of collision jet ventilation affects the mixing degree of hot air flow and cold air flow. Therefore, according to different air outlet heights, the temperature and velocity distribution characteristics of collision jet hot air heating room are studied in this paper. The results show that only when the air supply speed is low, the temperature near the ground increases with the decrease of the air outlet height, and the range of outdoor invasion of cold air is reduced. Although reducing the height of the tuyere can increase the utilization rate of heating energy in the room and reduce the air flow velocity above the ground, it increases the air flow velocity near the ground; because the temperature near the ground is high, it can make up for the shortage that the blowing feeling is too large because of the excessive speed, so it will not cause the discomfort of the personnel because of the blowing feeling.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU832

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