本論文探討具有單一點熱源的兩並聯房間使用機械設備提供驅動力的抽取通風模式之重要無因次參數。兩個並聯房間透過隔板的開口連接，其中上游房間具有單一固定浮力通量點熱源，稱為浮力源房間；下游房間具有抽取設備，稱為抽取房間，兩個房間有各自的開口連接至外界環境。模擬室內通風的實驗使用縮尺壓克力模型、沉水馬達與鹽浴法~(Salt bath method)進行，以沉水馬達模擬抽取設備所提供之慣性力，以鹽水及清水之密度差模擬室內環境產生的浮力。鹽浴模擬實驗與建築物熱浮力通風的方向是上下顛倒的，但是本研究使用的座標軸系統是一致的，垂直座標軸的原點設定在浮力源的位置。根據本實驗室先前的研究結果，當連接兩房間的開口位於垂直的隔板時，臨界流量會介於一個範圍，流場型式分為小流量模式、大流量模式及過渡流量模式。在小流量模式時，抽取房間連接外界環境的開口無流體通過，連接兩房間的開口完全在鹽水覆蓋的範圍內；在大流量模式時，抽取房間連接外界環境的開口引進外界的環境流體，與抽取房間內的鹽水混合，此時連接兩房間的開口完全在清水覆蓋的範圍內；在過渡流量模式時，抽取房間界面層高度位於連接兩房間的垂直開口區間內，由於連接兩房間的開口位於垂直隔板上，故連接兩房間的垂直開口區間大小會影響過渡流量範圍。理論分析模型使用點升流理論、虛擬原點修正理論、體積流率和浮力通量守恆方程式，在單一固定浮力通量點熱源，但不同抽取流率 (Qex)時，分別計算兩個並聯房間的界面層高度 (hf, hex)、密度層流體的縮減重力 (g'f, g'ex)，以及通過兩房間連接外界環境的開口的體積流率 (Qf, Qex0)之對應的方程式。無因次化分析以獨立的單一房間具有相同單一固定浮力通量點熱源驅動自然通風之體積流率 (QN)將兩並聯房間的推導結果無因次化，此外，使用浮力源房間的體積流率 (Qf)及界面層高度 (hf)將抽取流率 (Qex)及抽取房間界面層高度 (hex)對應的方程式無因次化。使用單一房間自然通風參數的無因次化理論模型顯示，當無因次抽取流量 (Qex/QN)等於1時，為小流量模式及過渡流量模式之無因次轉換流量，當無因次抽取流量 (Qex/QN)等於1.5時，為過渡流量模式及大流量模式之無因次轉換流量；實驗結果顯示，小流量模式及過渡流量模式之無因次轉換流量與理論模型之無因次轉換流量相同，過渡流量模式及大流量模式之無因次轉換流量則小於理論模型之無因次轉換流量，其無因次轉換流量約在無因次抽取流量~(Qex/QN)等於1.2時。使用單一房間自然通風參數的無因次化理論模型顯示，兩個並聯房間內的重要無因次參數主要由無因次抽取流量 (Qex/QN)決定。本研究進行的模擬實驗，當改變連接兩房間的開口位置時，獨立浮力源房間的自然通風之體積流率 (QN)也隨之變化，但是不同連接兩房間的開口位置之重要無因次參數 (Qf/QN, Qex0/QN, g'f/g'N, g'ex/g'N, hf/hN)在相同的無因次抽取流量 (Qex/QN)下有相似之結果，實驗結果與理論模型相當一致。使用浮力源房間參數的無因次化理論模型顯示，在小流量模式時，無因次抽取流量 (Qex/Qf)為常數1，故影響抽取房間無因次界面層高度之參數為hf^2/Aforce*及zv/hf；在過渡流量模式及大流量模式，連接兩房間的開口位置與密度源點間的距離減少時，抽取房間的無因次界面層高度 (hex/hf)隨無因次抽取流量~(Qex/Qf)上升而變化的幅度增加。由於其無因次化實驗結果為兩房間之實驗結果相除，故無因次化實驗結果與理論模型間有較大之差異。

This study investigates the important dimensionless parameters for mechanical extraction ventilation in two parallel-connected rooms having a heat source. In this configuration, the room with a heat source is denoted as the forced room, and the other room with a mechanical extraction device is denoted as the extracted room, either room has its own opening connecting to the exterior environment. In this study, the laboratory simulation experimentation uses a reduced-scale acrylic model of two parallel rooms, the suction pump, and the salt-bath technique to simulate the ventilation patterns inside the space. The suction pump is used to simulate the inertial force provided by the mechanical extraction device. The density difference between salt water and fresh water is used to simulate the buoyancy force in the indoor environment, which is in contrast to the orientation of the heat convection problems. The coordinate in this study is consistent, the origin of the vertical coordinates is located at the buoyancy source. Based on the previous study of our research team, when the internal opening is located on a vertical partition, there is a critical flow rate range, rather than a single value when that is on a horizontal one. The flow patterns are divided into three flow modes: the small flow rate mode, the large flow rate mode, and the transition mode. During the small flow rate mode, the extracted room environmental opening has no flow rate, and the internal connection opening is fully covered by salt water. During the large flow rate mode, the extracted room environmental opening introduces the exterior environment fluid that mixes with salt water in the extracted room, and the internal connection opening is fully covered by fresh water. During the transition mode, the extracted room interface level is between the vertical extent of the internal connection opening. Since the internal connection opening is on a vertical partition, the vertical extent size of the internal connection opening affects the range of the transition mode. The theoretical analysis model is based on the point plume theory, the virtual origin correction theory, and the conservation equations of volume flow rate and buoyancy flux. Then the important parameters including the interface levels (hf, hex), the reduced gravity values (g'f, g'ex), and the volume flow rates of the environmental connection openings (Qf, Qex0) are derived with the same heat source but at different extraction flow rates (Qex). The dimensionless analysis utilizes the volume flow rate of natural ventilation (QN) in a single room to non-dimensionalize the derivation results of two parallel-connected rooms, and the control extraction flow rate (Qex) is non-dimensionalized by the flow rate of natural ventilation in a single room (QN). Additionally, the interface level in the extracted room and the extraction flow rate are non-dimensionalized by the interface level (hf) and the volume flow rate in the forced room (Qf). The theoretical results using the parameters of the natural ventilation in a single room show that when the dimensionless extraction flow rate (Qex/QN) is equal to 1, it is the threshold flow rate between the small flow rate mode and the transition mode. When the dimensionless extraction flow rate (Qex/QN) is equal to 1.5, it is the threshold flow rate between the transition mode and the large flow rate mode. The experimental results show that the threshold flow rate between the small flow rate mode and the transition mode is close to that in the theoretical model, and the threshold flow rate between the transition mode and the large flow rate mode is smaller than that in the theoretical model, which dimensionless extraction flow rate (Qex/QN) is equal to 1.2. The theoretical results using the parameters of the natural ventilation in a single room show that the important dimensionless parameters are determined by the dimensionless extraction flow rate (Qex/QN). The experimental results show that different internal connection opening positions cause different volume flow rates of natural ventilation (QN) in a single room, but the important dimensionless parameters (Qf/QN, Qex0/QN, g'f/g'N, g'ex/g'N, hf/hN)have similar results in the same dimensionless extraction flow rate (Qex/QN), the experimental results are consistent with the theoretical model. The dimensionless theoretical results using the parameters of the forced room show that in the small flow rate mode, the dimensionless extraction flow rate (Qex/Qf) is a constant 1, and the parameters that affect the dimensionless interface level of the extracted room are hf^2/Aforce* and zv/hf. In the transition mode and large flow rate mode, when the distance between the internal connection opening position and the buoyancy source decreases, the rate of change of the dimensionless interface level in the extracted room (hex/hf) increases as the dimensionless extraction flow rate (Qex/Qf) increases. Since the dimensionless experimental results are obtained from the experimental results of two rooms, the dimensionless experimental results are inconsistent with the dimensionless theoretical results.

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