Disigning coolant channel on the firebox of liquid rocket engine to loxodrome ( equal - angle helix ) groove can improve firebox coolant capability greatly. because the width dimension of loxodrome groove is narrow and the depth is deep, some machining methods are incapable, such as end - milling or electrochemistry. according to the peculiarities, a cnc disk - cutter - milling method which is composed of five motion axes with four simultaneously interpolated ones is researched. because most firebox generatrix is composed of complex curves, it is very difficult to get cnc cutting program with manual means. in order to deal with the problem, the loxodrome mathematics model is studied, and an auto - programming software system is developed. the software system can generate cnc cutting program of loxodrome on many kinds of turned surface. the constriction - distension segment of firebox is the most representative workpiece. the sharp changing of its generatrix slope makes loxodrome milling difficult. with the theory analyzing and practice cutting experiment, some applied techniques, which include milling mode and direction, choosing cutter diameter and cutting start point setting, are developed. adopting the technology above, tens regular workpiece have been manufacturing. the two - year manufacture practice has confirmed the validity and feasibility of developed loxodrome coolant channel milling method. the developed technology is also worth to be referenced to other similar workpiece
將液體火箭發動機
燃燒室的冷卻通道設計為斜航線(等傾角螺旋線)槽形,可以大幅度改善
燃燒室的冷卻性能.斜航線冷卻槽的槽寬尺寸較小而槽深尺寸較大,所以無法使用棒銑刀銑削、電化學等加工方式.針對這些特點,提出了五軸控制、四軸聯動的數控片銑刀銑削加工方法.由於
燃燒室外表面的母線輪廓復雜,手工編制數控加工程序難度大.為了解決數控加工程序的編制問題,研究了斜航線的數學模型,開發了自動編程軟體系統.使用該系統,可以生成多種母線輪廓回轉體外表面上的斜航線數控加工程序.
燃燒室收斂-擴張段的母線斜率變化大,加工難度大,是斜航線冷卻通道加工的最典型工件.經過理論分析和實際切削實驗,研究了針對該類型工件的片銑刀直徑選擇、銑削方式和方向、刀具調整和起刀點的設置等多項實際的加工方案.採用上述的一系列技術,已經成功地加工了數十個合格工件.經過兩年多的實際生產過程應用,驗證了所開發的斜航線冷卻通道加工方法的正確性和可行性.這些加工技術的研製成功,對其他相
似類型零件的加工亦具有參考意義
This situation is quite reminiscent of earlier work on the combustion of carbon.
這種情況與在研究碳
燃燒方面的早期著作中所述的情況十分相
似。
And when jarvis lorry saw the kindled eyes, the resolute face, the calm strong look and bearing of the man whose life always seemed to him to have been stopped, like a clock, for so many years, and then set going again with an energy which had lain dormant during the cessation of its usefulness, he believed
這就是曼內特醫生此時的情況。羅瑞看到了他那
燃燒的目光堅定的面容沉著有力的表情和態度。當他心目中醫生過去的生活
似乎永遠像一座多年停擺的時鐘,可現在他確信他又以被廢棄后所積蓄的沉睡的精力嗒嗒地走了起來。
Thank you, stephen said, taking a cigarette. haines helped himself and snapped the case to. he put it back in his sidepocket and took from his waistcoatpocket a nickel tinderbox, sprang it open too, and, having lit his cigarette, held the flaming spunk towards stephen in the shell of his hands
海恩斯自己也取了一文,啪的一聲又把盒子關上,放回側兜里,並從背心兜里掏出一隻鎳制打火匣,也把它按開,自己先點著了煙,隨即雙手像兩扇貝殼
似的攏著
燃起的火絨,伸向斯蒂芬。
Which bring up a conclusion that the zoon model is not agree with the facts of fire experiment, hence the field model or the combined model is better for the simulation of fires in a large volume building
本文結合火災相
似模型實驗研究,對中庭建築火災過程進行了數值模擬研究,建立了火區
燃燒及蔓延過程與煙氣流動過程相互耦合的氣-固兩相火災模型。
The piston is now forced down, the burned gases expanding approximately adiabatically.
這時點
燃的氣體作近
似的絕熱膨脹而向下推動活塞。
The answer to the drip - drip - drip of dial - up, high - speed internet service fuels online entertainment. about 78 % of home internet users in the u. s. have broadband, up from less than 1 % in 1998
對滴水
似的貓上網方式的解決方案,高速網際網路服務點
燃了在線娛樂服務的火花。大約78 %的美國在家上網的人擁有高速寬帶,但這個數目在1998年曾經是1 %未滿。
Oxygen / fuel torch sets, propane torches, electric welders, portable disk or wheel grinders, portable lead pots and tar buckets are some examples of such tools and equipment
氧氣/
燃料焊槍、丙烷氣割炬、電焊工、手提圓盤或車輪磨工、手提鉛罐和瀝青桶都是類
似的工具和裝備的例子。
The pudding results from the failure of all the fuel to vaporize and from the sorting effect of the intake manifold.
積窪是全部
燃料蒸發得不充分和進氣歧管類
似影響的結果。
Already, soaring gasoline, diesel, jet fuel and residual fuel oil prices appear to be making a dent in demand - triggering restraint from consumers even before iea economies consider mandatory ones
飆升的汽油、柴油、航空
燃油和殘渣
燃料油價格,
似乎已經在抑制需求,甚至在國際能源機構成員國考慮採取強制措施前,消費者就已經在克制消費了。
Go in groups by car and the like, cut down on unnecessary use of fuel, gas and electricity whenever possible, use economical light bulbs etc. with the same or greater brightness
盡量多利用太陽能或任何形式的綠色能源,出門時採取共乘或其他類似的方式,盡可能減少不必要的燃料瓦斯和電力消耗,使用可以提供同樣亮度或照明度更大的省電燈泡。