水力石家莊風機廠風機的數值模擬和設計研究(1)

石家莊風機廠 石家莊風機 石家莊市風機廠 石家莊風機維修 石家莊風機銷售

摘要
隨著我國船舶事業的不斷發展,對船上一些輔助設備的要求越來越高。目前船用水力石家莊風機廠風機不僅要求防火、排煙,而且要求防爆、輕量化。國內對水力石家莊風機廠風機的設計大多采用常規設計方法,本文針對國內某一款高轉速、大排煙量的船用便攜式水力石家莊風機廠風機采用數值模擬和模型試驗相結合的方法進行了研究,填補了國內便攜式水力石家莊風機廠風機數值模擬研究方面的空白。本文主要進行了以下工作:
(1)水力石家莊風機廠風機的CFD模型研究
通過分析水力石家莊風機廠風機的結構和工作原理,對流體域進行了合理簡化,并在CFD軟件Fluent的前處理軟件Gambk中完成了水流場和空氣流場三維建模和網格劃分的研究;基于Fluent的標準1^模型對水輪機和石家莊風機廠風機的內部流動進行了數值模擬,將數值計算結果與試驗數據對比,水輪機模擬流量和試驗流量的相對誤差范圍為0.9%?7.6%,石家莊風機廠風機試驗全壓和模擬全壓的相對誤差范圍為4.7%~15.5%,基本能夠滿足計算要求,計算模型基本合理。
(2)基于多流場耦合的水力石家莊風機廠風機的性能預測
基于動網格技術,提出了一種多流場弱耦合計算方法:利用Fluent的UDF接口編程,使水力石家莊風機廠風機水流場和空氣流場的同步計算,并在每一個時間步長計算結束后,通過數據文件的讀寫交換兩個流場之間的相關數據,直至兩個流場達到完全匹配的穩定狀態。該方法不但可以完成水力石家莊風機廠風機整體性能預測,而且可以很方便的描述不同流場之間的相互關系,可以為水力石家莊風機廠風機的瞬態計算提供借鑒。
(3)水輪機的流場數值研究和結構改進
對水輪機核心部件一噴嘴和水渦輪的主要結構參數的變化引起水輪機的主要性能參數的變化情況作了分析,討論的結構參數包括水渦輪葉片型線、葉片數量、葉片高度、噴嘴數量、噴嘴內表面形狀、噴嘴斜射角和直徑比。模擬結果表明:修改后的葉片型線與常規型線相比水動性能略差,但加工性能大幅提高,可取代常規型線;葉片數量可在較大范圍內選擇,原模型水輪機葉片數的選擇合理;靠單純的增加葉片高度不能提升水輪機的性能;噴嘴數量的增多可有效增大出力;錐形噴嘴可有效減少壓力損失,增大水輪機的功率和效率;噴嘴斜射角越小,水輪機性能越好,但考慮到結構問題和加工難度,斜射角有一定的選擇范圍;通過增大噴嘴出口段直徑和葉片高度減小直徑比可明顯提高水輪機的過流能力和功率。根據這些研究對水輪機的結構進行了改進,改進后的水輪機功率在進口水壓為0.2MPa時增加了 39.4W,增長幅度達24.7%,進口水壓為0.7MPa時增加了 330.2W,增長幅度髙達31.7%。
(4)便攜式水力石家莊風機廠風機的設計研究
研究了便攜式水力石家莊風機廠風機的水動設計、結構設計和氣動設計。當縮放系數k為0.9~1.2時,不同水輪機的功率范圍為1000W?2200W,為水力石家莊風機廠風機的設計提供了更寬的功率選擇范圍;在保證結構強度滿足的條件下,完成了水輪機和石家莊風機廠風機最大尺寸的選擇;結合水輪機的性能曲線,給出了預測石家莊風機廠風機的設計風量和風壓范圍的方法。根據以上的研究成果,最終提出了一種水力石家莊風機廠風機設計方案,并通過設計案例進行了驗證.
關鍵詞:水力石家莊風機廠風機;數值計算;多流場耦合;水渦輪;噴嘴;設計方案

Abstract
With the continuous development of our marine industry, there are higher and higherrequirements on the marine auxiliary equipment. The marine water driven fans should be notonly fire prevention and smoke prevention, but also explosion-proof and lightweight. Most ofdomestic research on water driven fan adopt conventional design methods. One kind of marineportable water driven fan with high speed and large amount of smoke exhaust in the market wasresearched by adopting the method of numerical simulation and model test, which filled in theblank of the numerical simulation research on portable water driven fan. This paper carried outthe following work:
(1)CFD Model Research on the Water Driven Fan
After analysising the structure and working principles of the research object, the fluiddomain was simplified reasonably and by using the software Gambit the 3D Modeling andmeshing of the water flow field and air flow field were completed; Based on the standard k-￡epsilon model of the Fluent software, the internal flow field of the hydraulic turbine and the fanwere simulated, by comparing the results of numerical simulation date and experimental data,the relative error range between the calculated values for the flow rate of the hydraulic turbineand the measured values was 0.9%?7.6%, and the relative error range between the calculatedvalues for the total pressure of the fan and the measured values was 4.7%~15.5%, hich couldbasically meet the computing requirement. Thus the calculation model was basically reasonable.(2)Performance Prediction of the Water Driven Fan Based on Multi Field CouplingA multi field weak coupling calculation method was put forward: water flow field and airflow field are calculated at the same time by using Fluent UDF to program and control theprocess,and after the completion of calculation of each time step, data exchanges between thetwo flow field by reading and writing data files, until two flow field match and become steady.
This method can not only complete the performance prediction of water driven fan,but alsoeasily describes the relationship between different flow fields and provides reference for thetransient calculation of the water driven fan.
(3)The Flow Field Numerical Study and Structure Improvement of the Hydraulic TurbineThe changes of the main hydraulic turbine performance parameters caused by the changesof the structure parameters of the turbine and nozzle which are the main parts of the hydraulicturbine were analyzed. The structure parameters discussed include the type line, the number andthe height of hydraulic turbine blades,nozzle number, nozzle inner surface shape, oblique angle,as well as the cooperative relationship between the hydraulic turbine and nozzle. Simulation
results show that: the hydrodynamic performance of the modfied blde type line is a little lessthan that of the conventional line, but the processng performance can be improved obviously,so the modified blade type line can replace the conventional line; the blade number is availableto choose in a wide range, and the turbine blade number of the original model is reasonable; Byincreasing height of the turbine blade simply cannot improve the performance; The addition ofnozzle number can ffectively increase the output; Conical nozzle can effectively reduce thepressure loss,increase the power and efficiency of the turbine; The smaller the nozzle obliqueAngle is, the better the performance of the turbine will be, but considering the structure and theprocessing difficulty, oblique Angle should be in a certain range; By increasing the nozzle outletdiameter and blade height at the same time to decrease the diameter ratio, the flow capacity andpower of the turbine can be obviously improved. According to the study, the structure of theturbine was improved. When the inlet pressure was 0.2Mpa, the increasement and the grow rateof the turbine power were 39.4W and 24.7%,and when the inlet pressure was 0.7Mpa,theincreasement and the grow rate were 330.2W and 31.7%.
(4)The Design Researches of the Potable Water Driven FanThe hydraulic design, structure design and aerodynamic design of the portable water drivenfan were tudied. When scaling coefficient k is 0.9-1.2, the power range of different turbine is1000W?2200W,which provides wider power range for the design of the fan; nder thecondition of meeting the structural strength requirement, the selection of the urbine and fanmaximum size were completed; Combined with turbine performance curve, the way topredicting the design flow rate and total pressure of the fan was given. A design scheme of thewater driven fan was proposed at last, and was verified through a design case.Key words: water driven fan; numerical calculation; multi flow field coupling;hydraulic turbine; jet; design scheme