局部排氣導管設計程式的資料結構與計算驗證

Developing a Program on the Local Exhaust Duct Design-Data Structure and Validation on Computation

為解決局部排氣裝置的設計難題，開發完成一套可在個人電腦視窗環境下操作的局部排氣導管設計程式。此程式依 ACGIH 的靜壓平衡概念，可根據使用者所設定的氣罩風量需求以及導管搬運風速需求決定局部排氣裝置中各導管的管徑以及排氣機的性能需求，期使局部排氣裝置能以合理的能源消耗達到所需的控制效果。在程式開發過程中，以資料結構設計與計算驗證較為關鍵。本文即針對此二問題進行探討。在資料結構方面，採用串聯序列與二元樹處理導管與配件資料，使系統資源得以有效率應用。在計算驗證方面，則以現有文獻計算範例以及實驗室模型試驗與程式結果比對，確認計算結果的準確性。根據實驗室量測結果顯示，程式計算所得風量值與靜壓值與實際量測值的最大差異分別在 10% 與 20% 之間。

A Windows-based program was developed to solve the design problems related to the local exhaust system. Based on the design procedure recommended by ACGIH, the program gives diameters of the ducts and fan performance requirement according to the required flow rate of each hood and transportation velocity in each duct. This effort will result in a local exhaust system which can achieve required control performance with reasonable power consumption. This paper concentrates on the data structure design and computation validation of the program. Both are critical problems for the program development. The data structures linked list associated with binary tree are employed to store the data related to the ducts and fittings. This achieves an efficient use of the system resources. The validations were performed by comparing the computed results with the existing examples shown in several references, as well as the measurements from the models in laboratory. The correctness of the computation then was confirmed. According to the observation carried out in the laboratory, the maximum relavtive differences between measurement and computation in flow rate and static pressure are 10% and 20%, respectively.