發(fā)布時間：2018-02-15 14:51

  本文關鍵詞： 氣膜冷卻 復合冷卻 氣熱耦合 多場耦合 熱應力　出處：《中國科學院研究生院(工程熱物理研究所)》2015年碩士論文　論文類型：學位論文

【摘要】：現(xiàn)代燃氣輪機的透平葉片已經(jīng)發(fā)展出了氣膜冷卻、對流冷卻和沖擊冷卻等多種冷卻方式相結合的冷卻形式,采用氣熱耦合的方法預測透平葉片的表面溫度分布及換熱特性,利用多場耦合分析來評價冷卻結構,具有十分重要的意義。本文對氣熱耦合狀態(tài)下的平板氣膜冷卻與平板復合冷卻的綜合冷卻效果和壁面換熱情況進行了較為詳細的研究,并運用多場耦合分析對復合冷卻平板的冷卻結構進行了評價。搭建了平板耦合實驗臺和紅外熱像儀圖像采集與數(shù)據(jù)處理系統(tǒng),采用紅外測溫技術測量了耦合狀態(tài)下氣膜冷卻平板與復合冷卻平板耦合壁面的表面溫度分布,進而得出綜合冷卻效果的分布。采用氣熱耦合方法研究了吹風比、氣膜孔孔型和Bi數(shù)等參數(shù)對平板氣膜冷卻與復合冷卻的綜合冷卻效果、壁面換熱特性的影響。結果表明,耦合狀態(tài)下平板氣膜冷卻在整個耦合壁面上的綜合冷卻效果都大于零；在氣膜孔出口上游,隨著吹風比的增加,綜合冷卻效果逐漸升高；在氣膜孔出口下游,采用圓柱孔時在低吹風比時的綜合冷卻效果更好,而采用扇形孔時則在高吹風比時的綜合冷卻效果更好;Bi數(shù)的減小使整個耦合壁面的綜合冷卻效果分布變得更加均勻,同時耦合壁面熱流為正的區(qū)域逐漸減小。與氣膜冷卻相比,采用復合冷卻的方式,明顯改善了耦合壁面的冷卻效果；隨著吹風比的增加,整個耦合壁面上的綜合冷卻效果都隨之升高；復合冷卻中的氣膜冷卻平板采用扇形孔時耦合壁面的綜合冷卻效果在高吹風比時要明顯好于圓柱孔,沖擊冷卻中沖擊孔的布置方式及沖擊靶面距離都對復合冷卻的綜合冷卻效果分布有一定的影響；Bi數(shù)減小能使復合冷卻中氣膜孔出口上游耦合壁面的綜合冷卻效果分布更加均勻,而對下游耦合壁面的綜合冷卻效果和整個主流側耦合壁面的換熱系數(shù)分布影響較小。運用多場耦合分析方法,以熱應力為參數(shù)對復合冷卻平板的冷卻結構進行評價,研究了吹風比、氣膜孔孔型和沖擊冷卻結構對氣膜冷卻平板熱應力分布的影響。結果表明,熱應力集中主要發(fā)生在氣膜孔周邊位置,具體位置因孔型而有所不同,吹風比增加會使熱應力集中現(xiàn)象更加明顯,沖擊冷卻結構也會對熱應力分布產(chǎn)生一定影響。
[Abstract]:The turbine blades of modern gas turbines have developed a variety of cooling methods, such as film cooling, convection cooling and impact cooling. The surface temperature distribution and heat transfer characteristics of turbine blades are predicted by gas-heat coupling method. It is very important to evaluate cooling structure by using multi-field coupling analysis. In this paper, the comprehensive cooling effect and wall heat transfer of flat film cooling and plate composite cooling under gas-heat coupling state are studied in detail. The multi-field coupling analysis is used to evaluate the cooling structure of the composite cooling plate, and the image acquisition and data processing system of the plate coupling test bench and infrared thermal imager is built. The surface temperature distribution of the coupled wall of the gas film cooling plate and the composite cooling plate was measured by using infrared temperature measurement technique, and the distribution of the integrated cooling effect was obtained. The blowing air ratio was studied by using the gas-heat coupling method. The effects of hole shape and Bi number on the comprehensive cooling effect and the heat transfer characteristics of the flat film cooling and composite cooling are studied. The results show that the integrated cooling effect of the flat film cooling on the whole coupled wall is greater than zero in the coupled state. In the upper reaches of the outlet of the film hole, the comprehensive cooling effect increases gradually with the increase of the blowing ratio, and the comprehensive cooling effect is better when the cylinder hole is adopted at the low blowing ratio downstream of the outlet of the film hole. When the fan hole is used, the comprehensive cooling effect is better when the air blowing ratio is high. With the decrease of Bi number, the integrated cooling effect distribution of the whole coupled wall becomes more uniform, and the area where the heat flux of the coupled wall becomes positive gradually decreases. Compared with the film cooling, the heat flux of the coupled wall decreases gradually. The cooling effect of the coupling wall is improved obviously by using the compound cooling method, and the comprehensive cooling effect on the whole coupling wall increases with the increase of the blowing air ratio. The integrated cooling effect of the coupled wall surface of the gas film cooling plate with a fan hole is obviously better than that of a cylindrical hole when the air blowing ratio is high. The arrangement of the impact hole and the distance of the impact target surface have certain influence on the comprehensive cooling effect distribution of the composite cooling. The decrease of Bi number can make the integrated cooling effect distribution of the upstream coupling wall of the gas film hole in the composite cooling more uniform. But it has little influence on the cooling effect of the downstream coupled wall and the distribution of the heat transfer coefficient of the whole mainstream side coupling wall. The cooling structure of the composite cooling plate is evaluated by using the multi-field coupling analysis method and the thermal stress as the parameter. The effects of blowing ratio, film hole pass and impact cooling structure on the thermal stress distribution of the film cooling plate are studied. The results show that the thermal stress concentration mainly occurs in the peripheral position of the film hole, and the specific position varies with the pass type. The increase of blowing ratio will make the thermal stress concentration more obvious, and the impact cooling structure will also have a certain effect on the thermal stress distribution.
【學位授予單位】：中國科學院研究生院(工程熱物理研究所)
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TK471

【參考文獻】

相關期刊論文 前1條

1 Zhang Hongjun;Zou Zhengping;Li Yu;Ye Jian;Song Songhe;;Conjugate heat transfer investigations of turbine vane based on transition models[J];中國航空學報(英文版);2013年04期

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本文編號：1513523