Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/2408
標題: 再生型迴轉式空氣預熱器熱傳特性的數值研究
Numerical Studies on the Heat Transfer Characteristics for the Regenerative Air Preheater
作者: 顧宏基
Ku, Hong -Chi
關鍵字: air pre-heater
空氣預熱器
heating elements
cold end temperature
cold end corrosion.
熱元件
冷端溫度
冷端腐蝕
出版社: 機械工程學系所
引用: 參考文獻 1.STEAM,its generation and use 40th Edition, Babcock & Wilcox a McDermott company. pp.19-9 ~11,1992。 2.Bahnke, G.D. and Howard, C.P.,"The Effect of Longitudinal Heat Conduction on Periodic-Flow Heat Exchanger Performance",ASME Journal of Engineering for Power,Series A,Vol.86 1964,pp.105-120。 3.Chung-Hsiung Li,"A Numerical Finite Difference Method for Performance Evaluation of a Periodic-Flow Heat Exchanger",Journal of Heat Transfer,AUGUST 1983,Vol.105,pp 611-617。 4.Chi-Liang Lee,"The Optimal Analysis of Thermal Performance in Rotary Heat Exchanger",Thesis for Master of Science,Department of Mechanical Engineering,Tatung Institute of Technology,JUNE 1992。 5.Chi-Liang Lee,"”The Study of Thermal Efficiency of the Gas Air Heater(GAH) By Several Fuel in Co-generation System",行政院國家科學委員會專題研究計畫成果報告。計畫編號:NCS 90-2213-E-237-001,AUGUST 2001~JULY 2002。 6.R.B. Holmberg,"Heat and Mass Transfer in Rotary Heat Exchanger With Nonhygroscopic Rotor Materials",Transactions of the ASME,MAY 1977,vol. 99,pp.196-202。 7.包德梅,趙振寧,徐治皋,"Matrix Calculating Method in Dynamic Analysis of Regenerative Air Preheater",鍋爐技術,SEP. 1998,pp.6-10。 8.Wei Pan,Zuo-he Chi,Ge Li,Rong-Hua Sun,Hao Zhou,Xiao Jlang,Ke-Fa Cen,"Experimental and Numerical Mode Studies on Cold End Metal Temperature of 600MW Rotating Air Heater",Journal of Zhejiang University(Engineering Science),Vol.36 No.5,SEP. 2002,pp.494-497。 9.Hua-Jin Hu,Zhi-Gao Xu,"Calculating Method Study of the Heat Transfer Characteristics for the Tri-Sector Air Prehaater",Power Engineering,FEB 1998,vol.18 No.1,pp. 54-57。 10.Jun-hu Zh,Wei-Juan Yang,Yan-Tao Jin,Zhi-Jun Zh,Xin-Yu Cao,Ke-Fa Cen,"Research on the Heat Balance Calculation of the Tri-Section Regenerative Air Prehaeter",Power Engineering,DEC 2003,vol.23 No.6,pp.2810-2813。 11.Wei LENG,Dao-Lun Chen,Zhi-Lun Zhang,"Heat Exchange Calculation of a Regenerative Air Heater with Analytical Method",Proceedings of the CSEE,FEB. 2005,Vol.25 No.3,pp. 141-146。 12.Chang-quing Li,Chang-Liang Liu,"The Dynamic Model of Regenerative Air Preheater for Power Plant",Journal of North China Institute of Electric Power,1993,No.3,pp.71-76。 13.Ljungstorm Air Preheater Maintenance Seminar, June 1993, ABB Air Perheater INC. 。 14.M. Necati Ozisik,”Finite Difference Methods in Heat Transfer",1994,CRC Press,INC.。 15. Heat Transfer wit Application,International Edition,KIRK D. HAGEN.。
摘要: 摘要 在大型發電用鍋爐中,為降低鍋爐燃氣排放溫度,以及提高鍋爐效率,通常會裝置迴轉式空氣預熱器,以作為鍋爐熱回收裝置,空氣預熱器轉子是不斷的旋轉的,燃氣與空氣不斷的交替流經作為熱交換的金屬熱元件,金屬溫度成週期性的波動,熱元件的金屬溫度量測比較困難,本研究的目的在於建立數值分析的模型,計算迴轉式空氣預熱器內部的流體與金屬熱元件的溫度場變化特性,並以台中火力發電廠八號機為實例,將數值計算值與實際運轉進行比較。 研究方法是基於能量守恆的觀點,以及基本的熱傳導方程式,分別以準維及二維的數學模型推論迴轉式空氣預熱器內部的熱傳導行為,其中準維模式忽略金屬熱傳導效應,二維模式則考慮熱金屬傳導的影響,二者皆使用數值計算方法,並運用電腦程式演算以快速演算求出數值解。二維模式係使用有限差分的數值方法,進行模擬空氣預熱器運轉時,能量傳遞的現象,計算出流體與熱元件的金屬溫度分佈情形。 研究結果顯示結果良好,不論準維、二維的數值模擬結果與實際運轉現象接近,燃氣出口溫度誤差為分別為-0.70%與-1.29%,空氣出口溫度誤差分別為3.52%與3.11%。若考慮空氣洩漏的影響,則經過洩漏修正後的誤差在空氣側為0.43%,在燃氣側誤差為1.07% 。分析結果也印證空氣預熱器內部金屬溫度分佈對空氣預熱器冷端腐蝕、硫酸銨及硫酸氫銨堵塞等現象的影響。 最後本研究利用此分析模型,改變空氣預熱器的設計參數及運轉參數,探討各參數改變時對熱交換器性能的影響。結果顯示,對於火力發電用鍋爐的迴轉式空氣預熱器而言,對流熱傳導對迴轉式空氣預熱器的熱交換性能影響,遠大於熱元件金屬熱傳導,改變金屬熱傳導係數,對於迴轉式空氣預熱器的熱傳特性影響不大。
Abstract In most fossil power plant, the steam generator is always installed with rotating air per-heater as a heat recovery equipment which can decrease the flue gas exhaust temperature so that the boiler efficiency could be enhanced. The rotor of air pre-heater is continuously rotating, flue gas and air flow across the mental heating elements of the air pre-heater. The metal temperature changes periodically. It is difficult to measure the metal temperature, and this study will establish a theoretical model to calculate the temperature fields of the fluids and heating elements which are inside the rotating air pre-heater. The calculated results will be compared with the operation of the unit 8 of Taichung Power Station which was taken as an actual example. Methods of this studies were based on the conservation of energy and basic heat transfer equations. Using quasi-dimensional and two-dimensional mathematical model respectively to derive the heat transfer behaviors inside the rotating air per-heater. In quasi-dimensional model, the effect of metallic heat conduction is neglected, but it will be taken into account in the two-dimensional model. Both quasi and two dimensional model are solved with numerical method and computer programs were developed to find out the solutions rapidly. A finite difference method is used to simulate the heat energy transfer between the fluids and the rotor matrix in the two-dimensional system. Results of calculation show that both the two methods have good results when compared with the actual operation data from Taichung Power Station. The error is-0.70% and-1.29% on the flue gas side respectively, while 3.52% and 3.11% on the air side respectively. While considering the air leakage problem, after correction by air leakage in the air heater, the error becomes 0.43% on the gas side and 1.07% on the flue gas side respectively. The calculated results also show that the metal temperature distribution inside the rotating air per-heater will cause the phenomenon of cold end corrosion and the plugging by ammonium sulfate. Using this mathematical model, finally, we will change the designed and operation parameters of the rotating air per-heater to evaluate the influences on its effectiveness. Furthermore, results of calculation show that the heat convection effect does more influence than metal conductivity to the effectiveness of the rotating air per-heater that utilized for power plant, it will be almost no apparent variation to the heat transfer behavior while the coefficient of the metal conductivity was changed.
URI: http://hdl.handle.net/11455/2408
其他識別: U0005-0607201009163600
文章連結: http://www.airitilibrary.com/Publication/alDetailedMesh1?DocID=U0005-0607201009163600
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