The welding technology of francis turbine runners is optimized from the view of subsection welding and local heating by numerical simulation. the result shows that welding residual tensile stress appears in the weld and its area nearby, and peak stress appears in the dangerous area of blades after practising quondam welding technology ; welding residual tensile peak stress in the dangerous area of blades can be decreased by welding both ends earlier and then welding middle section later during subsection welding, and decreasing effect on welding residual stress of the subsection welding is related to the weld length of blade outlets and welding direction of each subsection ; decreasing effect on residual stress of the local heating is direct proportional to heating time, heating temperature, heating area, and inversely proportional to cooling area, and welding residual tensile peak stress in the dangerous area is decreasing trend earlier, and then increasing trend later with heated location increased
本文利用數值模擬手段對轉輪的焊接工藝從分段焊和局部加
熱兩個方
面進行了優化,結果表明:採用普通工藝焊接時,葉片焊后殘余拉應力出現在焊縫及其附近區域,並且在葉片出水邊的熔合線附近(危險區域)出現了峰值;在採用優化的分段焊時,先焊兩端后焊中間的方法可以降低葉片危險區域的焊接殘余拉應力峰值,降低效果與葉片出水邊焊段長度、焊縫各段的焊接方向有關;局部加
熱法降低轉輪危險區域殘余應力的效果主要與加
熱時間、加
熱溫度以及加
熱面積成正比,與冷卻
面積成反比,並且危險區域的殘余應力隨加
熱區域的增大呈先降低后升高的趨勢。
A rational range of saturation pressure is proposed and a brief introduction of the combustion control system adopted in phase - change heaters is made
研究了介質飽和壓力對相變換
熱加
熱爐受
熱面布置的影響,提出了介質飽和壓力的合理范圍,對相變換
熱加
熱爐燃燒控制系統作了簡要介紹。
The temperature distribution on the high temperature side of an electric tunnel furnace is analysed and simulated on the basis of the principle of thermal radiation by the way of thb ( thermal heat balance ). the heated silicon carbon sticks are decomposed into innumerable tiny heating faces, which exchange the heat with the heated materials. a numerical model based on the radiation intensity law is constructed to calculate the energy absorbed by the heated materials and simulated by a computer. the results showed that the even distribution of temperature can be obtained by optimizing the arrangement of the silicon carbon sticks according to the calculation results to make the structure design more reasonable. these calculation results have been used in the practical designs and the expected objectives achieved
利用
熱輻射原理,採用
熱平衡法對電
熱隧道窯的高溫恆溫區溫場進行了分析和模擬.計算中將發
熱棒分解為無數微元發
熱面與燒結體進行
熱交換,依據輻射強度定律,建立了燒結體接收能量的數學模型,並用計算機進行了模擬計算.結果表明,依據模擬結果來優化硅碳棒的排布,可使結構設計更加合理,進而可以獲得分佈均勻的恆溫區溫場.計算結果已在窯爐設計中應用,實踐效果良好
Subsequently, we introduce some monitoring model and implement currently used, then we release our model, which suit the 1 # boiler of beilun power plant, on the basis of the models before. our model is subdivided into three categories, each category suit the heat exchanger of deferent type : the furnace, convective surface and trisector air preheater, all these categories use clean factor as the indication of the soot desposition level
首先介紹了鍋爐灰污染危害的現狀,對比研究了國內外的灰污染監測手段和監測模型,並針對北侖1 #鍋爐,建立了鍋爐各受
熱麵灰污染監測模型,這些監測模型分為爐膛、對流受
熱面、以及三分倉空預器三種類型,採用清潔因子作為受
熱麵灰污染狀況的指標。
The article takes a 600mw natural cycle drum boiler ( soot blow using steam ) as investigating object, establishes soot accumulation loss and soot blowing energy loss models for its water cooling wall, superheater, economizer and air preheater respectively, set up instructions for soot blower operating. simulating calculation results are compared with site data to verify usefulness of key models. the article introduced the operation optimizing design of soot blowers of yanzhou no2 power plant based on theoretical research
本文以600mw汽包自然循環鍋爐(蒸汽吹灰)為具體分析對象,分別建立其水冷壁、過
熱器、省煤器、空預器的積灰損失和各受
熱面吹灰能量損失的模型,建立相應的吹灰器運行規則指導,對設計中的關鍵模型問題,通過模擬計算及與現場數據作比較的方法,驗證其可用程度。
Abstract : based on the analysis of influence of tubular rib construction on heat transfer area on steel blank and heat transfer space in furnace, a t - shape support system for tubular rib is presented, by which the construction of wholly overhead furnace hearth can be realized for large and medium scale continuous reheating furnaces, making furnace gases to come into full contact with steel blank, raising space utilization ratio of furnace chamber and improving heat exchange
文摘:分析了爐筋管結構形式對傳
熱空間、坯料受
熱面積的影響;提出採用t形支撐技術優化爐筋管,可實現大、中型連續加
熱爐的全架空爐底,使爐氣與坯料表
面充分接觸,提高爐膛空間利用率,可較大幅度提高爐膛
熱交換。
3. on boiler retrofit, the calculation of fuel burning, the heat calculation of boiler inside structure and convection section, and the design of structure parameter of feed water heat exchanger are made. the flue gas channels " resistance calculation and the boiler strength verifying are also carried out. replacement of water cooling wall improves heat exchanging and decreases loss of heat radiant
對鍋爐本體進行了燃料燃燒計算、爐膛結構
熱力計算、對流受
熱面結構
熱力計算、鍋爐給水加
熱器結構參數設計、煙道阻力計算及鍋爐元件強度校核等;改進了水冷壁布置使換
熱效果更好,減少輻射換
熱損失;改進對流段結構,更充分的利用爐膛出口煙氣余
熱,提高
熱效率;並且進行了煙氣阻力計算、
熱效率計算和能量平衡測試,對改進后的稠油燃料和改進前進行了對比,燃燒狀況和
熱效率有明顯改善。
Temperature and its control of heated wall
熱風爐受
熱面壁溫控制技術研究
All the investment is taken back in half of heating period. the larger the area of the heating plant is, the more distinct the economy benefit is
半個採暖期,即可收回全部投資費用。若每個供
熱站的供
熱面積越大,經濟效益越明顯。
And the results of calculation and numerical simulation indicate, without increasing the intrinsic collector - junction area of power devices, collector - combed structure helps to raise the intrinsic heat - dissipating area and base ' s perimeter, improve heat - dissipating method of each cell of the chip, enhance the distribution uniformity of junction temperature and current of each cell of the chip, reduce the thermal resistance and raise the dissipation power pd and output power p0, fairly well relax the contradiction among frequency, out - put power and dissipation power of the devices, and further improve the devices " property against second breakdown
而計算分析和二維數值模擬分析結果表明:梳狀集電結(基區)結構在不增加器件本徵集電結
面積的條件下,增大了器件的本徵散
熱面積和基區周長,改進了每個子器件單元內的散
熱方式,提高了單元內結溫和電流分佈的均勻性,降低了器件的
熱阻,增大了器件的耗散功率和輸出功率,較好地緩解了目前傳統結構中頻率與功率、功耗的矛盾,並有利於改善器件抗二次擊穿的性能。
For long - term protection of heated pipelines, exhaust pipes, smoke stacks and other heated surfaces up to 550 - 600
長期保護加
熱管道、排氣管道、煙囪及其它溫度可高達550 - 600的受
熱面。
Treatment for three stubborn problems in the safe and economical operation of cfbc boiler wear prevention of wall and heating surface discharge and cooling of bottom slag
爐壁和受
熱面防磨的治理及爐底渣排放與冷卻
Coil tightly the stainless steel radiator wing around the electric heating pipe to enlarge the radiating area of the heating tube surface and the heater radiates more quickly, have higher heat use rate and the power density of the heater will be improved. structure sketch
分體機用翅片加熱器,是電加熱管上緊密繞制不銹鋼散熱翅片,它增大了加熱器表面的散熱面積,使加熱器散熱更快,熱利用率更高。