Effect Of Guide Plate On Indoor Air Flow Under Natural Ventilation

Under natural ventilation conditions,indoor ventilation volume is greatly affected by climate and season.It is difficult to control the uniformity and stability of natural ventilation flow direction.Therefore,the ideal thermal comfort environment and human comfort requirements are not achieved under long-term open doors and windows for natural ventilation.Under the action of some cross-hall wind,the air distribution and ventilation effect in some indoor areas are better,but some other important room areas may not be ventilated effectively because of the building structure,building orientation and indoor layout.Therefore,under the condition of natural ventilation,how to improve indoor air quality to meet the requirements of human comfort has become one of the urgent problems to be solved.This study hopes to achieve a more comfortable indoor natural ventilation environment by using a passive method and technology to guide natural wind in different directions and magnitude of forced wind speed through people's living and working space in a reasonable flow pattern.Referring to the engineering construction standard of Zhejiang Province "Design Standard for Wind and Thermal Environment of Residential Buildings" DB33/1111-2005,this paper divides the speed comfort zone under natural ventilation according to the regional characteristics and indoor working characteristics,taking into account the speed zone and thermal comfort.Based on the climate conditions of Hefei,the indoor space of buildings in Hefei is studied.The room model of 2.2m/s south wind speed in Hefei is 3.6m x 4.0m x 3.0m.The north-south opening area is 0.6m x 1.2m and 0.9m x 2.1m,the south opening height is 0.9m,the fixed diversion plate distance is 1.4m,the width of diversion plate is 1.2m and the height of diversion plate is 0.9m.The influence of guide plate on indoor air flow pattern under natural ventilation was analyzed and studied by combining numerical simulation with experimental measurement of equal-ratio model.The distribution of indoor air distribution under different hole width-height ratio and different hole shape was discussed.By means of simulation analysis and experimental verification,the calculation model was optimized,and the following conclusions were drawn:(1)The indoor air flow patterns of diversion plates with different width-height ratios of openings were different,keeping the inlet and outlet air pressure constant and the diversion plate position constant.The diversion plate has no openings,the proportion of indoor velocity comfort zone is the smallest,accounting for 6.30%;the diversion plate has a hole,the maximum value of velocity comfort zone appears when the ratio of width to height of the diversion plate is 8/6,accounting for 28.04%;the diversion plate has two holes,the maximum value of velocity comfort zone appears when the ratio of width to height of the diversion plate is 5/9,accounting for 35.51%;the diversion plate has three holes,and the speed is comfortable.The maximum value of the zone occurs when the ratio of width to height of the orifice is 3/11,accounting for 32.69%.(2)There is little difference in indoor air flow pattern with different orifice shape guide plates.When a diversion plate opens a hole,the shape of the diversion plate openings varies slightly,and the proportion of each speed zone varies slightly,55% in the low wind speed zone,25% in the comfortable speed zone and 19% in the high wind speed zone.When the diversion plate opens two holes,the shape of the diversion plate openings varies slightly,and the proportion of each speed zone varies slightly,65% in the low wind speed zone,21% in the comfortable speed zone and 21% in the high wind speed zone.Accounting for 13%.(3)Under the condition of natural ventilation,the size distribution of indoor comfort zone can be changed by reasonably setting the guide plate in Hefei area.(4)The velocity values of the measured points obtained from the experiment of the equal-ratio model are slightly larger than those of the simulated ones,but the overall trend of the experimental and simulated data is consistent.