Investigation of turbulent large-scale structures in indoor air flow in a wide parameter range using experiments in compressed sulphurhexafluoride

使用压缩六氟化硫实验研究宽参数范围内室内气流中的湍流大型结构

• 批准号: 230511119
• 负责人: Professor Dr. André Thess
• 金额: --
• 依托单位: Institut für Technische Thermodynamik (Stuttgart)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/230511119?language=en
• 关键词: Investigation; turbulent; large; scale; structures

The accurate prediction of the spatial and temporal distribution of temperature and velocity in indoor air flows as well as in flows in passenger cabins is of great importance for human health as well as for the economic use of energy for heating and air conditioning. Although there has been considerable progress in both experimental and numerical fluid dynamics in predicting indoor air flows, it is still difficult or even impossible to accurately predict the flow field on spatial scales of the order of several meters and on temporal scales of several hours. The reason for this difficulty is in the fact that indoor air flows represent a blend of forced and natural convection. This type of flow is often referred to as mixed convection and is more difficult to predict than pure forced and pure natural convection. The goal of the present project is to overcome the lack of understanding of the mechanisms of turbulent structure formation in flows relevant to indoor air flows. Based on the unique experimental facility SCALEX which was constructed and commissioned in the framework of the joint DFG-project entitled Formation of structures in turbulent mixed convection in rooms and passenger cabins in the period from 2007 to 2012, the applicant of the present project has demonstrated for the first time that it is possible to reproduce indoor air flows in small scale experiments using compressed sulphurhexafluoride at pressures of 5 bar. Based on this preliminary work the specific goal of the present project consists in a comprehensive analysis of turbulent structures for a range of parameters which is wider than in any previously conducted laboratory experiment. The goal shall be achieved in three steps, namely 1 - investigation of symmetry braking mechanisms, 2 - investigation of hysteresis and 3 - investigation of transient problems. Although the present project is focussed on fundamental research issues, the considered geometry represents a highly simplified model of an aircraft passenger cabin. Therefore the expected results of the project will not only contribute to fundamental fluid dynamics but will - in the long term - also be useful in the aeronautic industry as well as in the development of trains and automobiles.

准确预测室内气流和客舱气流的温度和速度的时空分布对人体健康以及采暖和空调能源的经济利用具有重要意义。虽然在预测室内空气流动的实验和数值流体动力学方面已经取得了相当大的进展，但是仍然很难甚至不可能准确地预测几米量级的空间尺度和几小时的时间尺度上的流场。这种困难的原因在于室内空气流动是强制对流和自然对流的混合。这种类型的流动通常被称为混合对流，比纯强迫对流和纯自然对流更难预测。本项目的目标是克服缺乏了解的机制，湍流结构的形成有关的室内空气流动的流动。基于独特的实验设施SCALEX，该实验设施是在2007年至2012年期间在DFG联合项目“房间和客舱中湍流混合对流结构的形成”的框架内建造和投入使用的，本项目的申请人首次证明，使用压缩的六氟化硫在小规模实验中再现室内空气流动是可能的压力为5 bar。基于这一初步工作，本项目的具体目标是对一系列参数的湍流结构进行全面分析，这些参数比以前进行的任何实验室实验都要宽。该目标应分三步实现，即1 -对称制动机制的调查，2 -滞后的调查和3 -瞬态问题的调查。虽然本项目的重点是基础研究问题，所考虑的几何形状代表了一个高度简化的飞机客舱模型。因此，该项目的预期结果不仅有助于基础流体动力学，而且从长远来看，还将有助于航空工业以及火车和汽车的发展。