大空间竖向热羽流与横向冷射流的相互运动液态模型实验研究
摘 要
高大空间建筑分层空调普遍采用喷口侧送的气流组织形式，而目前该气流组
织形式的设计计算大多只是简单地套用半经验公式，这种方法忽略了室内热源形
成的热羽流对射流轨迹的影响，因此气流组织计算结果必有一定误差，从而会对
预期的室内空气分布及热舒适性造成一定的偏差。
本文在对竖向热羽流和横向冷射流相互运动初步认识和探索的基础上，以相
似理论为依据，设计搭建了用于模拟大空间建筑室内气流运动的液态模型实验台，
对大空间建筑中常见的竖向热羽流与横向冷射流的相互运动规律进行实验研究，
为科学合理地进行大空间分层空调喷口送风气流组织设计计算提供参考。
本文在相似理论的基础上，通过对气流运动控制方程组和液态流体运动控制
方程组的分析，结合几何相似、动力相似和运动相似分析，分析了气流运动和液
态流体运动的相似性，并推导得到液态模型实验的相似准则数为 Re、Ar 和Pr（Sc），
考虑到自模化现象和忽略次要因素，确定以 Ar 作为主要准则数，以此作为设计搭
建液态模型实验台的依据。
根据液态模型实验模拟原理和相似条件的要求，以大空间实验基地为原型设
计搭建了几何比例尺为 1：20 的液态模型实验台，完成了液态模型实验台的主体
设计，包括冷射流系统、热羽流系统、环境空间系统和测量控制系统的设计，以
及羽源注入口的设计和冷射流喷口的设计。借助速度比例尺 Cu解决了冷射流与热
羽流系统的相似同步性问题。液态模型实验台具有一定的开放性，为大空间实验
基地中的后续课题研究提供实验平台。
利用液态模型实验台对多股冷射流、多股热羽流及多股冷射流与多股热羽流
的相互运动进行实验研究，得到了不同工况下冷射流的速度分布及运动轨迹，实
验结果表明：单股冷射流及其在单股热羽流作用下的轴心轨迹理论值与实验值吻
合较好；在竖向热羽流作用下，横向冷射流的运动轨迹发生偏转，以初速为 8m/s
的单股冷射流为例，在 500W 和1000W 热源形成的单股热羽流作用下，其轴心轨
迹在作用点下游相距 6m 处分别上升了约 0.20m 和0.52m；受竖向热羽流的作用，
作用点下游附近冷射流的速度扩散范围变小，以初速为 5m/s 的单股冷射流为例，
在500W 热源形成的单股热羽流作用下，在作用点下游相距 2m 处的速度扩散范围
减小了约 12%；竖向热羽流与横向冷射流的作用点不同，冷射流运动轨迹和速度
扩散受到的干扰作用大小也不同，在冷射流初段，惯性力较强，不易受热羽流干
扰，而在冷射流末段，惯性力减弱，易受热羽流干扰；多股冷射流的叠加效应明
显，两股和三股初速为 5m 的冷射流叠加后，在 x=16m 处，其轴心轨迹分别上升
了约 0.91m 和1.48m，速度扩散范围分别增加了约 11%和19%。
通过对热羽流介质进行染色，观察不同强度的横向冷射流对竖向热羽流的作
用，实验结果表明：液态模拟可以较好的再现热羽流的发生、发展、运动过程；
热羽流与冷射流的相对强弱决定了二者相互作用的结果，以热源强度为 1000W 的
热羽流为例，在 v0=2m/s 的冷射流作用下，其运动轨迹虽然发生偏转，但是仍可保
持竖直方向上的运动趋势，在 v0=8m/s 的冷射流作用下，热羽流则完全融入冷射流
中，并与冷射流主流一起向前运动；多股竖向热羽流的叠加，可以增强热羽流的
运动趋势，其对冷射流的抬升作用也随之增强。
本文在实验测试及数据分析的基础上，分析了大空间建筑内两种不同属性气
流之间的相互作用，为科学合理的进行大空间分层空调喷口送风气流组织设计计
算提供参考。
关键词：热羽流 冷射流 相互运动 液态模型 相似理论
ABSTRACT
In large space buildings, lateral supplying air by jets is a common form of air
distribution for the stratified air conditioning. This form of air distribution is based on
semi-empirical formula, but the semi-empirical formula neglects the influence of the
thermal plume generated by heat source. Therefore air distribution calculation using this
method will have some errors, which will cause certain deviation to the prospective air
distribution and indoor thermal comfort.
This study is based on the similarity theory and the preliminary recognition of the
interaction between vertical thermal plume and horizontal cold jet. A liquid model
experiment table is established to simulate the air movement in large space buildings. A
liquid model experimental study method is used in this paper to research the interaction
between vertical thermal plume and horizontal cold jet. The purpose of this study is to
provide reference for scientific and rational air distribution calculation of the large space
buildings.
The theory foundation of this paper is similarity theory. The control equation
groups of air movement and liquid movement is analyzed, and the similarity of air
movement and liquid movement is proved according to the similarity of geometric,
dynamic and movement. Re, Ar and Pr (Sc) are deduced as the similar criterion
numbers of the liquid model experiment. Considering the self-simulating and secondary
factor, Ar is choosed as the main similar criterion number, and it is taken as the design
foundation of the liquid model experiment table.
On the basis of similar criterion and the principle of liquid model experiment, a
liquid model experiment table is established according to the large space experiment
center, and its geometric scale is 1:20. The design of liquid model experiment table
includes the cold jet part, the thermal plume part, the environmental space part and the
measurement and control part. The inlets of plume and jet are designed specially, and a
series of difficulties are solved, such as similarity coincidence of plume and jet parts.
This table has some openness, so it can provide an experiment platform for the
following study of the large space experiment.
Liquid model experiments are taken to simulate multiple thermal plumes, multiple
cold jets and the interaction between them, and the velocity distribution of cold jet is
obtained, which is under the action of different condion of vertical thermal plumes. The
experimental results show that, the trajectory of jet and the trajectory of jet under the
action of thermal plume for liquid simulation are almost coincided with the theoretical
values. Under the influence of vertical thermal plume, the downward trend of cold jet is
hindered, and it leads to the upward of its original trajectory. Takes single cold jet with
initial velocity of 8 m/s for instance, under the action of single thermal plume of 500W
and 1000W, its trajectory raise 0.20m and 0.52m respectively 6m away from the action
point. Under the influence of vertical thermal plume, velocity diffusion range of cold jet
becomes smaller after the action point. Takes single cold jet with initial velocity of 5
m/s for instance, under the action of single thermal plume of 500W, its velocity
diffusion range becomes smaller by 12% where is 2m away from the action point. The
degree of influence depends on the position of action point. In the initial section of cold
jet, inertial force is relatively strong, so it is not easier being influenced. In the terminal
section, inertial force becomes weak, so it is easier being influenced by thermal plume.
Superposition effect of the multiple cold jets is notable. When two and there cold jets
are superimposed, at the point of x=16m, trajectory raise 0.91m and 1.48m respectively,
and velocity diffusion range becomes smaller by 11% and 19% respectively.
The medium of the thermal plumes is dyed, so the action of horizontal cold jet to
vertical thermal plume can be observed, and the results shows that, liquid model
experiment can well recurrence the starting, developing and the movement of thermal
plume. The relative strength of the thermal plume and cold jet determines the interaction
results between them. Takes single thermal plume generated by heat source of 1000W
for instance, under the action of cold jet with initial velocity of 2 m/s, its trajectory
becomes bending, but it still keeps the upward trend. Under the action of cold jet with
initial velocity of 8 m/s, it involves into the jet completely. Superposition effect of the
multiple thermal plumes is also proved through the experiment, and multiple plumes
have relatively greater influence on cold jet because of the superposition effect.
Based on the experimental test and result analysis, the interaction between two
different types of airflow in large space buildings, it can provide reference for scientific
and rational air distribution calculation of the large space buildings.
Key Word：thermal plume，cold jet，interaction，liquid model
experiment，similarity theory
目 录
中文摘要
ABSTRACT
第一章 绪论 ......................................................... 1
1.1 课题研究背景及意义 ........................................... 1
1.2 国内外研究动态 ............................................... 3
1.2.1 热羽流运动与冷射流运动研究现状........................... 3
1.2.2 液态模型实验研究现状..................................... 4
1.3 本文主要研究内容 ............................................. 7
1.3.1 液态模型实验流体介质的选择............................... 7
1.3.2 研究工作内容............................................. 7
第二章 竖向热羽流与横向冷射流相互运动液态模型实验理论分析 ........... 9
2.1 引言 ......................................................... 9
2.2 相似理论与模型实验 .......................................... 10
2.2.1 相似三定理.............................................. 10
2.2.2 模型实验的实现.......................................... 11
2.2.3 模型实验的意义.......................................... 13
2.3 气流运动和液态流体运动的控制方程组 .......................... 13
2.3.1 气流运动的控制方程...................................... 13
2.3.2 液态流体运动的控制方程.................................. 14
2.4 热羽流与冷射流相互作用液态模型实验相似准则的导出 ............ 14
2.4.1 相似准则的导出方法...................................... 14
2.4.2 液态模型实验相似准则的导出.............................. 15
2.5 非等温气流运动与盐水运动的相似性分析 ........................ 18
2.5.1 热羽流运动与盐水运动的相似性分析........................ 18
2.5.2 冷射流运动与盐水运动的相似性分析........................ 18
2.5.3 利用盐水模型模拟热羽流与冷射流的相互运动................ 19
2.6 本章小结 .................................................... 20
第三章 液态模型实验台的设计与搭建 .................................. 21
3.1 引言 ........................................................ 21
3.2 实验台的设计目标和要求 ...................................... 22
3.2.1 实验台的设计目标........................................ 22
3.2.2 实验台的设计要求........................................ 22
3.3 液态模型实验台设计方案 ...................................... 24
3.3.1 确定模型实验台相似比例尺及模型参数...................... 24
3.3.2 模型实验台总体设计方案.................................. 27
3.3.3 冷射流系统.............................................. 29
3.3.4 热羽流系统.............................................. 31
3.3.5 主环境空间.............................................. 33
3.3.6 模型实验台典型工况实验流程举例.......................... 34
3.4 实验台计量设备的修正 ........................................ 35
3.4.1 转子流量计介质性质的修正................................ 35
3.4.2 转子流量计修正举例...................................... 35
3.5 实验台技术难点及解决方案 .................................... 36
3.5.1 注入口装置的设计........................................ 36
3.5.2 主环境水箱非受限性和开放性设计.......................... 38
3.6 本章小结 .................................................... 40
第四章 竖向热羽流与横向冷射流相互运动液态模型实验及分析 ............ 42
4.1 引言 ........................................................ 42
4.2 实验方案 .................................................... 42
4.2.1 实验目的................................................ 42
4.2.2 实验内容................................................ 42
4.2.3 实验工况................................................ 43
4.3 实验测试 .................................................... 44
4.3.1 测试仪器................................................ 44
4.3.2 测点布置方案............................................ 45
4.3.3 实验流程................................................ 46
4.4 测试结果及分析 .............................................. 47
4.4.1 单股冷射流的运动分析及实验验证.......................... 47
4.4.2 单股冷射流与单股热羽流相互运动分析及实验验证............ 50
4.4.3 单股冷射流与两股热羽流相互运动分析...................... 55
4.4.4 单股冷射流与三股热羽流相互运动分析...................... 59
4.4.5 两股冷射流的叠加运动分析................................ 62
4.4.6 三股冷射流的叠加运动分析................................ 63
4.4.7 两股冷射流叠加与两股热羽流相互运动分析.................. 65
4.4.8 单股热羽流的运动分析.................................... 67
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作者：牛悦
分类：高等教育资料
价格：15积分
属性：100 页
大小：6.59MB
格式：PDF
时间：2025-01-09
