二維熱流效應對電化學加工反求工具形狀之分析; Two-dimensional two-phase numerical model for tool design in electrochemical machining

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Title:	二維熱流效應對電化學加工反求工具形狀之分析;Two-dimensional two-phase numerical model for tool design in electrochemical machining
Authors:	張啟生;Chi-Sheng Chang
Contributors:	機械工程研究所
Keywords:	電化學加工;反求法;二相流;ECM;inverse problem;two-phase flow
Date:	2000-12-20
Issue Date:	2009-09-21 11:32:07 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	在電化學加工(Electrochemical Machining，簡稱ECM)過程中，產生的氣泡及熱量均會改變電解液的導電性質，而相關的熱流場參數，如壓力、溫度、流速等亦隨流場之形狀不同而有所變化，故欲準確地預測加工中各項參數的變化情形尚非易事。以往的研究分析中，皆只侷限在一維熱流場的模擬分析，但在加工區域變化較為劇烈時，電解液與氫氣的流動受到流場區域變化的影響，不再只是一維的現象，有必要以二維的熱流場模式加以分析。本文嘗試以體適合法(Body-Fitted Method)產生格點，並以二維二相之不同速度同溫度模式，分析二維熱流效應，以了解電極間隙內，各項熱流參數諸如體積分率、流場、壓力及溫度等之分佈情形。並利用崁入法反求工具形狀，以加工出所欲得之工件形狀。以完整傅利葉級數擬合工件形狀，來降低相對誤差。藉由本文之分析，結果顯示所預測之工件外形與Hopenfeld和 Cole所做的實驗值十分接近。而二維熱流效應在加工區域流場形狀變化很大時非常顯著，增加供給電解液之流量只能輕微的減輕其影響。若流場形狀變化不大時，二維熱流效應較小，可用一維熱流模式分析以節省計算時間。 Tool design in electrochemical machining is investigated which includes the effects of thermal-fluid properties of the electrolyte. A finite Fourier cosine series, constructed by both even and odd harmonics, is used in the electrode representation to reduce the relative error. A two-dimensional two-phase numerical model is applied to predict the thermal-fluid field. Results show that, as the curvature of the electrode shape varies seriously, the two-dimensional phenomenon of the flow is apparent and the two-dimensional model should be used in the numerical simulation. Larger flow rate of the electrolyte can lightly reduce the two-dimensional effects. As the curvature of the electrode shape varies mildly, one-dimensional analysis is accurate enough and capable to reduce the calculating time.
Appears in Collections:	[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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