多污染源置换通风的数值模拟
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摘要
置换通风是一种全新的通风方式，可获得较高的空气品质和节能效果以及具有较高的通风效率。它的高效合理性和较高的热舒适性以及其节能性为其应用开辟了广阔的前景。但是目前研究尚有不足。置换通风系统在实际应用时是多污染热源并存的，而目前对有多个污染源的深入研究甚少，大多数学者都是围绕单一污染热源而展开研究的。为此提出了置换通风中多个污染热源的问题，通过对多个污染热源置换通风系统的数值模拟，研究其送风参数、热源特性等对室内流场、温度场等的影响规律。
本文在实验模型的基础上，经简化建立了有三个污染源的置换通风三维稳定传热、流动的物理模型和数学模型。流动和换热的模拟，采用K／ε模型，并在能量方程中考虑浮升力的作用，在壁面附近粘性支层中，采用壁面函数法。利用模拟软件PHOENCS，对进风速度变化、进风温度变化和室内热源的位置变化和热源表面温度及热流量变化等工况进行模拟研究。
通过数值模拟，深入研究多污染源置换通风的热力分层高度、垂直温度分布、通风效率、舒适性、节能性等问题，获得以下主要研究成果：
(1)置换通风房间的热力分层高度随送风量的增大而增大、随送风温度的降低而有所降低。为避免“吹风感”，当室内热源强度在280W／m~2以下时，应控制送风速度不超过0.3m／s。为满足热力分层高度及工作区热舒适性等要求，当室内热源强度在150W／m~2以下时，应使送风温度与室内工作区温度的温差最大不超过4～5℃。
(2)热源特性对置换通风的热力分层高度、通风效率等产生影响。热源射流速度在一定范围内越大，热力分层高度越低；热源温度升高，热力分层高度下降；热源的分散性越大，热力分层高度越低；但分散到一定程度时，热力分层高度、通风效率将不受影响。对多热源的通风房间，若热源强度不超过500W／m~2，其通风效率、热力分层高度及热舒适性均能符合有关标准，可考虑采用置换通风；为获得良好的置换通
西安建筑科技大学硕士学位论文
风效果，房间热源应尽量紧凑布置。
（3）多热源与单一热源置换通风房间的热力分层高度、垂直温度分布等是不同
的。在二者热源热流量相同条件下，多热源置换通风的热力分层高度明显下降，在热
力分层高度以上区域温度和排风温度有所下降，且多热源的过渡区厚度较单一热源的
要大，因此，与单一热源相比，多热源对置换通风系统很不利。
（4）数值计算结果与实验测试值基本吻合，说明数值模拟所选用的计算模型、
设置的边界条件、计算结果等是可靠的。
Displacement ventilation is a completely new ventilation way, through which aims such as gaining higher air quality, econmizing energy and getting better ventilation efficiency are realized. The reasonableness of good efficiency, improved hot comfortability and economy energy all open up a promised prospect for applying the ventilation. But research on it is still quite limited. The system can't remove multi-polluting heat sources when used. Present literature do little research on multi-polluting heat sources, while more scholars concentrate on single-polluting heat sources. Therefore, the problem is raised. By establishing numerical simulation on multi-polluting heat sources in the system , effects of air-in parameters and heat sources characters on flow field and temperature field are analized.
Based on experimental models, the paper sets up three-dimensional steady heat transfer and flow physical model and mathematical model on a three polluting heat sources after simplification. In flow and heat transfer simulation, K/E model is applied, effect of buoyancy is accounted in energy equation; in viscosity lamination access to the wall, wall functions are used. With software PHOENCS, changes of in-air velocity, in-air temperature, positions of inner heat sources, surface temperature and heat flux quantity are simulated and researched.
The numerical simulation helps to further research in heat lamination height, vertical temperature distribution, ventilation efficiency, comfortability and energy energy economy in the system. Main results are as follows:
(1) Heat lamination height rises along with air-in flow rising and decreases with air-in temperature decreased. To avoid being bio wed , when innner heat source intensity is under 280w/m2, control air-in velocity within 0.3m/s. To satisfy requests like heat lamination height and hot comfortability in working areas when the intensity reach below 150w/m2, make temperature differece between air-in temperature and working areas temperature no bigger than 4-5Cc.
(2) Heat sources effects on heat lamination height and ventilation efficiency of displacement ventilation. The bigger heat source injecting velocity is, the lower heat lamination height is; the higher heat source temperature is, the lower heat lamination height is; the more obvious dispersion the heat source is, the lower heat lamination height is, but if it's dispersed to a degree, heat lamination height and ventilation efficiency will not be affected. In multi-heat sources ventilation room, if heat source intensity is no bigger than 500 w/m2, ventilation efficiency, heat lamination height and hot comfortability
conform to the standard. So under this condition, apply displacement ventilation. To get better displacement ventilation effect, heat sources should be compactly placed.
(3) Differnce between multi-heat .sources and single heat source displacement ventilation room on their heat lamination height and vertical temperature distribution and so on. When heat fluxes of the two conditions are equal, heat lamination height of multi-heat sources displacement ventilation reduces apparently, both zonal temperature and out-air temperature decrease somewhat and mushy region thichness in multi-heat sources is thicker than single heat source. Therefore, compared to single heat source, multi- heat source is disadvantageous to displacement ventilation.
(4) Numerical calculating results approximately coincide with experimental data, which means computer models,boundary conditions and calculating results in numerical simulation is reliable.
本文在实验模型的基础上，经简化建立了有三个污染源的置换通风三维稳定传热、流动的物理模型和数学模型。流动和换热的模拟，采用K／ε模型，并在能量方程中考虑浮升力的作用，在壁面附近粘性支层中，采用壁面函数法。利用模拟软件PHOENCS，对进风速度变化、进风温度变化和室内热源的位置变化和热源表面温度及热流量变化等工况进行模拟研究。
通过数值模拟，深入研究多污染源置换通风的热力分层高度、垂直温度分布、通风效率、舒适性、节能性等问题，获得以下主要研究成果：
(1)置换通风房间的热力分层高度随送风量的增大而增大、随送风温度的降低而有所降低。为避免“吹风感”，当室内热源强度在280W／m~2以下时，应控制送风速度不超过0.3m／s。为满足热力分层高度及工作区热舒适性等要求，当室内热源强度在150W／m~2以下时，应使送风温度与室内工作区温度的温差最大不超过4～5℃。
(2)热源特性对置换通风的热力分层高度、通风效率等产生影响。热源射流速度在一定范围内越大，热力分层高度越低；热源温度升高，热力分层高度下降；热源的分散性越大，热力分层高度越低；但分散到一定程度时，热力分层高度、通风效率将不受影响。对多热源的通风房间，若热源强度不超过500W／m~2，其通风效率、热力分层高度及热舒适性均能符合有关标准，可考虑采用置换通风；为获得良好的置换通
西安建筑科技大学硕士学位论文
风效果，房间热源应尽量紧凑布置。
（3）多热源与单一热源置换通风房间的热力分层高度、垂直温度分布等是不同
的。在二者热源热流量相同条件下，多热源置换通风的热力分层高度明显下降，在热
力分层高度以上区域温度和排风温度有所下降，且多热源的过渡区厚度较单一热源的
要大，因此，与单一热源相比，多热源对置换通风系统很不利。
（4）数值计算结果与实验测试值基本吻合，说明数值模拟所选用的计算模型、
设置的边界条件、计算结果等是可靠的。
Displacement ventilation is a completely new ventilation way, through which aims such as gaining higher air quality, econmizing energy and getting better ventilation efficiency are realized. The reasonableness of good efficiency, improved hot comfortability and economy energy all open up a promised prospect for applying the ventilation. But research on it is still quite limited. The system can't remove multi-polluting heat sources when used. Present literature do little research on multi-polluting heat sources, while more scholars concentrate on single-polluting heat sources. Therefore, the problem is raised. By establishing numerical simulation on multi-polluting heat sources in the system , effects of air-in parameters and heat sources characters on flow field and temperature field are analized.
Based on experimental models, the paper sets up three-dimensional steady heat transfer and flow physical model and mathematical model on a three polluting heat sources after simplification. In flow and heat transfer simulation, K/E model is applied, effect of buoyancy is accounted in energy equation; in viscosity lamination access to the wall, wall functions are used. With software PHOENCS, changes of in-air velocity, in-air temperature, positions of inner heat sources, surface temperature and heat flux quantity are simulated and researched.
The numerical simulation helps to further research in heat lamination height, vertical temperature distribution, ventilation efficiency, comfortability and energy energy economy in the system. Main results are as follows:
(1) Heat lamination height rises along with air-in flow rising and decreases with air-in temperature decreased. To avoid being bio wed , when innner heat source intensity is under 280w/m2, control air-in velocity within 0.3m/s. To satisfy requests like heat lamination height and hot comfortability in working areas when the intensity reach below 150w/m2, make temperature differece between air-in temperature and working areas temperature no bigger than 4-5Cc.
(2) Heat sources effects on heat lamination height and ventilation efficiency of displacement ventilation. The bigger heat source injecting velocity is, the lower heat lamination height is; the higher heat source temperature is, the lower heat lamination height is; the more obvious dispersion the heat source is, the lower heat lamination height is, but if it's dispersed to a degree, heat lamination height and ventilation efficiency will not be affected. In multi-heat sources ventilation room, if heat source intensity is no bigger than 500 w/m2, ventilation efficiency, heat lamination height and hot comfortability
conform to the standard. So under this condition, apply displacement ventilation. To get better displacement ventilation effect, heat sources should be compactly placed.
(3) Differnce between multi-heat .sources and single heat source displacement ventilation room on their heat lamination height and vertical temperature distribution and so on. When heat fluxes of the two conditions are equal, heat lamination height of multi-heat sources displacement ventilation reduces apparently, both zonal temperature and out-air temperature decrease somewhat and mushy region thichness in multi-heat sources is thicker than single heat source. Therefore, compared to single heat source, multi- heat source is disadvantageous to displacement ventilation.
(4) Numerical calculating results approximately coincide with experimental data, which means computer models,boundary conditions and calculating results in numerical simulation is reliable.
引文
1．马仁民．连之伟．置换通风几个问题的讨论．暖通空调．2000，30(4)：18
2．马仁民．置换通风的通风效率及其微热环境评价．暖通空调．1997，27(4)：1
3．周鹏．李强明．置换通风与冷却顶板．暖通空调．1998，28(5)：1
4．朱能．刘珊．置换通风与冷却顶板的热舒适性研究．制冷学报．2000，4：64
5．孟广田．李强民．置换通风的热舒适分析与评价．建筑热能通风空调．2000，1：21
6．李强民．置换通风原理设计及应用．暖通空调．2000，30(5)：41
7．倪波．双热源置换通风的实验研究．暖通空调．2002，2(5)：17
8．岑鸣．倪波．上海体育馆置换通风系统设计研究．暖通空调．2000，30(5)：5
9．狄长元．李光华．吴云翔．置换通风系统在水电站厂房中的应用．人民长江．2000，31(12)：37
10．张俊梅．沈国民．谢军龙．应用CFD方法确定置换通风系统的设计参数．建筑热能通风空调．2001，2：17
11．刘传聚．周林光．置换通风的数值模拟．通风除生．1998，1：4
12．龚光彩．CED技术在暖通空调制冷工程中的应用．暖通空调．1999，29(6)：25
13．赵蕾．矩形平面热源上方浮力射流流量近似计算公式．西安建筑科技大学学报．1998，30(4)：364
14．许志浩．蔡德源．高大厂房分层供热数值模拟研究．西安交通大学学报．1997，32(3)：288
15．杨沫．王育清．德燕弘等．具有表面辐射的导热和对流耦合问题的数值计算方法．西安交通大学学报．1992，26(6)：25
16．倪波．置换通风的实验研究．暖通空调．2000，30(5)：2
17．傅志成．沈国明．谢军龙等．置换通风空调系统的研究．鄂州大学学报．1999，6 (3)：10
18．赵彬．李先庭．彦启森．室内空气流动数值模拟的风口模型综述．暖通空调．2000，30(5)：33
19．方祥位．李建中．魏文礼．紊流数值模拟的现状及发展．陕西水力发电．2000，6 (1)：16
20．鞠硕华．姜允涛．周祖东．置换通风空调房间气流组织的数值模拟．低温建筑技术．2001，2：41
21．陶文铨．数值传热学．西安：西安交通大学出版社，1988
22. HaKon Skislad Displacement Ventilation. Tautoy England, Research Studies PressLtd, 1994
23. Nielsen PV. Description of supply opening in numerical distribution, ASHRAE Trans, 1992:963-988
24. Peter V Nielson. The box method-a practical procedure for introduction of an air terminal device in CFD calculation. Dept of Building Technology and Structural Engineering. Aalborg University, Danmark, 1997
25. YanHuo, Jianshun Zhang, Chiayu Shawetal. Anew methed to describe the diffuser boundary conditions in CFD simulation. ROOM VENT' 96, 1996:1-8
26. QingYan Chen. Computational fluid dynamics for HVAC: successes and failures. ASHRAE Trans, 1996:178-182, 185-186
27. M F Brunk. Cooling Ceilings-An Opportunity to Reduce Energy Costs by Way of Radiant Cooling. ASHRAE. Transaction, 1996, Vol. 99
28. Holger Kruhne. Klaus Fitzner. Energie--and Stoffttansport in Raumen mit Quellufrstromung. HLH. 1997, 46
29．范存养．办公室下送空调方式的应用．暖通空调．1997，27(4)：30
2．马仁民．置换通风的通风效率及其微热环境评价．暖通空调．1997，27(4)：1
3．周鹏．李强明．置换通风与冷却顶板．暖通空调．1998，28(5)：1
4．朱能．刘珊．置换通风与冷却顶板的热舒适性研究．制冷学报．2000，4：64
5．孟广田．李强民．置换通风的热舒适分析与评价．建筑热能通风空调．2000，1：21
6．李强民．置换通风原理设计及应用．暖通空调．2000，30(5)：41
7．倪波．双热源置换通风的实验研究．暖通空调．2002，2(5)：17
8．岑鸣．倪波．上海体育馆置换通风系统设计研究．暖通空调．2000，30(5)：5
9．狄长元．李光华．吴云翔．置换通风系统在水电站厂房中的应用．人民长江．2000，31(12)：37
10．张俊梅．沈国民．谢军龙．应用CFD方法确定置换通风系统的设计参数．建筑热能通风空调．2001，2：17
11．刘传聚．周林光．置换通风的数值模拟．通风除生．1998，1：4
12．龚光彩．CED技术在暖通空调制冷工程中的应用．暖通空调．1999，29(6)：25
13．赵蕾．矩形平面热源上方浮力射流流量近似计算公式．西安建筑科技大学学报．1998，30(4)：364
14．许志浩．蔡德源．高大厂房分层供热数值模拟研究．西安交通大学学报．1997，32(3)：288
15．杨沫．王育清．德燕弘等．具有表面辐射的导热和对流耦合问题的数值计算方法．西安交通大学学报．1992，26(6)：25
16．倪波．置换通风的实验研究．暖通空调．2000，30(5)：2
17．傅志成．沈国明．谢军龙等．置换通风空调系统的研究．鄂州大学学报．1999，6 (3)：10
18．赵彬．李先庭．彦启森．室内空气流动数值模拟的风口模型综述．暖通空调．2000，30(5)：33
19．方祥位．李建中．魏文礼．紊流数值模拟的现状及发展．陕西水力发电．2000，6 (1)：16
20．鞠硕华．姜允涛．周祖东．置换通风空调房间气流组织的数值模拟．低温建筑技术．2001，2：41
21．陶文铨．数值传热学．西安：西安交通大学出版社，1988
22. HaKon Skislad Displacement Ventilation. Tautoy England, Research Studies PressLtd, 1994
23. Nielsen PV. Description of supply opening in numerical distribution, ASHRAE Trans, 1992:963-988
24. Peter V Nielson. The box method-a practical procedure for introduction of an air terminal device in CFD calculation. Dept of Building Technology and Structural Engineering. Aalborg University, Danmark, 1997
25. YanHuo, Jianshun Zhang, Chiayu Shawetal. Anew methed to describe the diffuser boundary conditions in CFD simulation. ROOM VENT' 96, 1996:1-8
26. QingYan Chen. Computational fluid dynamics for HVAC: successes and failures. ASHRAE Trans, 1996:178-182, 185-186
27. M F Brunk. Cooling Ceilings-An Opportunity to Reduce Energy Costs by Way of Radiant Cooling. ASHRAE. Transaction, 1996, Vol. 99
28. Holger Kruhne. Klaus Fitzner. Energie--and Stoffttansport in Raumen mit Quellufrstromung. HLH. 1997, 46
29．范存养．办公室下送空调方式的应用．暖通空调．1997，27(4)：30