本研究主要在提供一個新的安全防護氣囊基本構型品的設計方向，應用計算流體力學數值方法模擬分析不同幾何尺寸氣體產生器之近音速或超音速流場狀態。主要在提供吸氣式後座乘員安全防護氣囊基本構型品設計的方向與建立氣囊開啟動態數值模擬分析，以現有計算流體力學數值方法模擬分析吸氣式充氣模組流場狀態；吸氣式充氣模組之氣體產生器尾焰噴流藉由一噴嘴（Nozzle）以近音速或超音速的紊流流場噴出，其尾焰裙邊會匯入大量的外圍冷空氣並進行能量的傳遞。在一封閉空間中外圍冷空氣可藉由進氣道吸入其中，冷空氣由進氣道被吸入的氣體量會因著噴流流場的流速、週遭環境的溫度與壓力、噴嘴與進氣道的幾何形狀及其相對應的裝置位置等因素而改變，且受後端氣囊在震波衝擊下的開啟運動而影響。應用Fluent商業軟體對充氣器之充氣過程進行動態流場數值模擬，分析充氣器之充氣效果，並探討影響吸氣比之因素，藉由數值模擬分析，可獲得最佳吸氣率效能的吸入氣體量、噴嘴與進氣道之幾何大小、裝置位置與噴流流速彼此間的對應關係，參考此經驗以獲得最佳氣體產生器設計。氣體產生器內流場實驗量測不易擷取，應用內部流場計算數值結果，可提供氣體產生器設計者迅速瞭解內部流場流況，並製作一組充氣動態之實體可視化觀測模型進行動態觀測，以有效改善與調整充氣器設計。

Purpose-The study of the aspirated inflator on side airbag modulus can provide a new direction for airbag design. The main purpose of this project is to design， model and test a new inflator.
Design/methodology/approach-Computational fluid dynamics is used to analyze the supersonic turbulent flow of a gas generator in different geometries. The strong inject flow of gas generator will induce outside cold air to enter into the airbag and cool down the high temperature gas flow.Findings-The inner flow field changes quickly according to 1) gas inject velocity; 2) surrounding air temperature and pressure， and 3)position of jet nozzle and air inlet. The aim of this project is to find an optimum position and geometry for gas generator and inlet opening that can provide a high aspiration ratio for the new design inflator.
Practical implications-Numerical simulation using FLUENT will provide an empirical relation of inject gas nozzle， inlet opening and gas inject velocity. Simultaneously， the flow field of this aspirated inflator can be obtained by numerical calculation without further experimental instrumentation. Originality/value-The new design of airbag will be effectively modified and improved. The results thus can provide a reference for numerical simulation and design improvement of airbags.