| The status of indoor airflow, especially the air distribution of great space, is an important issue in Heating, Ventilating, and Air Conditioning engineering. Due to the extreme complexity of turbulent structure, there is no way to solve the problem theoretically. Furthermore, the accuracy and the applicable scope of the simplified relations obtained from model test are still not satisfied. With the development of computer science, the computational fluid dynamics offers us a powerful means to make understanding of the indoor airflow of great space. Recently in the simulation of indoor airflow, mainly adopted is the turbulence model theory, RANS, which solves only the time-averaged flow field and cannot reveal the characteristics of the rapidly changing of turbulence. Particularly, large discrepancy results when solving non-isothermal indoor air flow with RANS.Large eddy simulation (LES), as a newly developed method for turbulent airflow simulation, has not only the advantage of smaller calculation effort but also achieve very high accuracy in most cases. At the same time the solution reserves the random characters of the flow field, which fits better with actual measurement than RANS does, and therefore, LES is showing its great superiority and powerful vitality. Since the LES has only been in its infancy of application in indoor air flow simulation, some fundamental problems remains to be studied systematically.The main work and the originality points of this dissertation could be concluded as the following parts:(1) To analyze systematically the mathematical model of LES of air flow in great space, under the case of isothermal and non-isothermal, as well as the combined action of buoyancy and strain. Some basic problems are studied about the LES application into airflow simulation of great space, such as boundary conditions, spatial difference scheme and time advancing scheme, time step etc., which creates the basis for the LES application to indoor airflow simulation.(2) Both the instantaneous and time averaged flow field of great space with multiple jets under isothermal and non-isothermal cases are explored with large eddy simulation method, and also discussed the dynamic characteristics and the law of fluidflow in the great space.(3) Based on the results of LES of the great space and the Fanger thermal comfort indexes, it is brought forward the concept of the series of dynamic thermal comfort evaluating indexes, which could be divided into thermal comfort index with time averaged properties PD, PPD, PMV, thermal comfort index with instantaneous properties IPD, IPPD, IPMV, and time averaged thermal comfort indexes TAPD, TAPPD, TAPMV, and transient situations time averaged thermal comfort indexes TTAPD, TTAPPD, TTAPMV. The differences among them and the calculation methods are discussed, and the four kinds of indexes are calculated with the thermal comfort index PD as an example.(4) Based on the LES results it is discussed the hot air stratification phenomena in air-conditioned buildings in the case with air supply and return registers on the ceiling and the case on the sidewall. The fundamentals of the hot air stratification are studied and the relations of estimating hot air stratification are brought forward.(5) With the advanced apparatus such as hot wire film anemometer IFA300 and laser particle field anemoscope (PIV), corresponding model test and site measurements have been done, which are compared with the simulation results and LES is proved a very promising method in air flow simulation indoor.
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