為了改善室內空間通風方式，以加裝通風系統提升房間空氣流動情形，本研究使用6 m × 6 m × 3.6 m房間尺寸等比例縮小30倍得到200 mm × 200 mm × 120 mm小型腔體，並使用通風系統的送風口寬度對腔體尺寸無因次化，以模擬在室內安裝通風系統之可行性，並可提供至現實全尺寸室內空間中作為參考示範。本次實驗使用顆粒影像測速儀(Particle Image Velocimetry, PIV)量測氣流在小型腔體內的變化。實驗方式為，將小型腔體放置在開放式風洞內，使用吸入式風扇提供腔體氣流，並固定腔體送風口速度與排風口尺寸，改變腔體送風口數量，分別為一、三、五個，在每個條件下量測腔體空氣交換率、各方向平均速度、各方向無因次化速度、動量通量以及紊流強度。
為固定腔體送風口速度，使用變頻器控制風洞的吸入式風扇轉速達成一致速度。因顆粒影像測速儀須將雷射光頁穿透實驗腔體，使雷射光頁照射到進入腔體內之示蹤粒子，達成散射目的，方能使得相機能拍攝到示蹤粒子，故在實驗腔體相機拍攝面與雷射照射面與使用透明壓克力組成，其餘部分為減少雷射光頁反光，使用霧黑壓克力作為腔體材料。為獲得時間平均速度場數據，使用顆粒影像測速儀在每種條件下都進行300組瞬時速度場量測，並將所有量測結果平均。
實驗結果顯示，在單送風口模式下，僅有送風口下方的扇形面積有明顯的氣流流動，且在靠近腔體壁面出現有微小回流現象。在三送風口模式下，還是能由紊流強度輪廓圖觀察出腔體內依然有部分區域氣流變動量極小。五送風口則是有著最大的氣流變動量。比較三種送風口數量的表現，三送風口與五送風口因為增加送風口數量改善氣流流動情況。在送風口數量選擇上，單送風口與五送風口並不適合作為此空間大小的通風裝置架構。單送風口的配置雖然能帶動腔體內空氣流動，但僅限於送風口下方區域，且無法抑制回流的現象，以現實情況來說，有可能導致人體呼吸道所散播的氣融膠持續存留在室內空間，而無法順利排出室內空間造成間接感染。五送風口在流動情況看似有著最佳表現，但因為過多的送風口數量導致送風流量遠大於排風流量，造成腔體內壓力梯度的產生，使得空氣進入腔體內速度急遽減緩，在調整送風速度上會出現困難。

In order to improve the ventilation mode of the indoor space and install a ventilation system to improve the air flow in the room, this study uses a small cavity of 200 mm × 200 mm × 120 mm to simulate the feasibility of installing a ventilation system in the room and provide a realistic Full size interior space as a reference demonstration. In this experiment, a particle image velocimetry (Particle Image Velocimetry, PIV) was used to measure the change of airflow in a small cavity.
The experimental method is to place a small cavity in an open wind tunnel, use a suction fan to provide air flow in the cavity, and fix the speed and size of the air outlet in the cavity, and change the number of air outlets in the cavity, which are 1, 3, and 5. Measure the cavity air exchange rate, average velocity in each direction, dimensionless velocity in each direction, momentum flux and turbulence intensity under each condition.

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