擬譜法分析孔隙介質二相流之最佳震動控制

PSEUDOSPECTRAL METHOD FOR SOLVING SEISMIC FORCE OPTIMAL CONTROL PROBLEM OF POROUS MEDIA TWO-PHASE FLOW

蔡昊宸(Hao-Cheng Tsai) ； 胡明哲(Ming-Che Hu) ； 許少瑜(Shao-Yiu Hsu)

《農業工程學報》 66卷1期 (2020/03) Pp. 21-26

https://doi.org/10.29974/JTAE.202003_66(1).0003

摘要

本研究建構擬譜法以處理最佳化控制問題，擬譜法的分析過程先離散化最佳化函數及其限制條件，並選取適當之節點逼近，便能使原問題轉變為離散之最佳化問題，再利用非線性最佳化演算法求解，便能得到此最佳控制問題之最佳控制解。本研究利用孔隙介質二相流之最佳震動控制問題進行案例分析，在多孔隙介質內的油滴因為毛細作用的抗力而被困在毛細管中不能輕易被抽出，因此在抽取過程中會額外施加一振動頻率，使油滴產生共振抵抗毛細作用的抗力，以提升油滴抽取的效率。本研究的最佳控制問題之控制變數為調整額外施加之振動頻率與外力，限制式為使油滴達到可抽出之最小距離，再以抽取過程中最低能量消耗為目標函數，本控制問題之最佳解將可提供油滴的最佳震動抽取控制。

關鍵字

擬譜法 ； 最佳控制 ； 孔隙介質二相流

並列摘要

This research aims to establish pseudospectral method to solve optimal control problems. Pseudospectral method converts optimal control problems into a nonlinear programming models, and then the optimal solutions of the models can be determined. The case study of this research constructs an seismic force optimal control problem of porous media two-phase flow. In the process of oil extraction, some oil might be remained in the crust because of the capillary tension and resistance of the in the porous media. To eliminate the trapped oil in the porous media, a excitation frequency is applied and causes oil blobs resonance. Because of the resonance, oil blobs can easily cancel out the resistance of capillarity and tension force. The seismic force optimal control model minimizes the energy consumption by adjusting the excitation frequency and extracting force.

並列關鍵字

Pseudospectral method ； Optimal control ； Two-phase flow in porous media

參考文獻

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