雙螺桿壓縮機具有高效率與高穩定性等特性，廣泛應用於冷凍系統、大樓空調與食品製造等多種產業，但減少低負載所產生振動與噪音是壓縮機業者重視的課題。本文建立一套數值計算程序，考慮不同轉子齒形及不同工作條件下，可快速計算螺桿轉子與容量調節滑閥所受之氣體力及氣體力矩結果，以評估對機體振噪之影響。程序以螺桿轉子齒形點資料為基礎，計算靜態與動態幾何特性，包括吸、排氣口與滑閥形狀設計，並結合熱力與流體力學計算得到工作腔氣體變動壓力，進而計算轉子及滑閥受到氣體之負載。本文分析兩種不同壓縮機型，除了探討不同負載下，滑閥及轉子受到氣體負載所造成之力及力矩變動差異，更將滑閥受力計算與CFD軟體模擬結果進行比對，證實本研究所建立之數值計算程序具有可靠性外，更可大幅縮短壓縮機設計與分析時程與成本，並有助於改善壓縮機之性能。

Twin-screw compressors have been widely used in various industrial applications such as refrigeration systems, air conditioners in buildings and food manufacturing due to their high efficiency and stability. However, the vibration and noise generated under low loading operation are still a concern for compressor manufacturers. This study proposes a numerical calculation procedure for quickly calculating the gas-induced forces and torques on the screw rotor pair and the sliding valve for oil-injection twin-screw compressors. In the beginning, the static and dynamic geometry characteristics, including the shapes of suction and discharge ports, and the slider valve, are calculated based on the discrete point data of rotor profile. These geometric data is further used in the thermo-fluid dynamics module to estimate the varying working gas pressure, which is then used in the calculation of gas-induced loads on the rotors and the sliding valve. Two different types of compressors are used in the discussions. The difference of gas-induced forces and torques on the rotors and the sliding valve for different loading conditions are analyzed. In addition, the numerical calculation results of gas-induced loads on the sliding valve are compared with the simulation results from CFD software. As shown in results, the numerical calculation model established in this study has the reliability and practicability to be applied in improvement of compressor performance, and reducing time and cost in the compressor design and analysis process.

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