本文選題：離心式通風(fēng)機　切入點：優(yōu)化設(shè)計　出處：《浙江大學(xué)》2011年碩士論文　論文類型：學(xué)位論文

【摘要】：前向離心式通風(fēng)機,如9-19、9-26系列,由于其具有較高的輸出壓力,因而廣泛應(yīng)用于物料輸送、鍛冶爐及高壓強制通風(fēng)。相比于后向風(fēng)機,前向風(fēng)機有效率較低、噪聲較高、工作范圍偏窄的缺點。本文主要針對前向離心式通風(fēng)機且以9-19風(fēng)機為設(shè)計實例,通過提出合理的氣動設(shè)計方法將前向葉片重新設(shè)計成后向葉片,并采用數(shù)值模擬方法進行分析和優(yōu)化,從而在保證滿足流量、壓力等條件下,提高風(fēng)機的效率。 本文的設(shè)計思想是基于離心風(fēng)機葉輪流道內(nèi)的流動特點,從葉輪流道內(nèi)的速度分布出發(fā),控制邊界層的增長、吸力邊邊界層分離、分層效應(yīng)及二次流,從而達到減弱尾流區(qū)、減小流動損失的目的。這使得本文的設(shè)計方法比傳統(tǒng)方法更符合實際流動狀況。氣動設(shè)計的主要步驟是：通過控制葉輪內(nèi)平均相對速度的分布,設(shè)計葉輪的幾何形狀,并采用一系列目標(biāo)函數(shù)和設(shè)計準(zhǔn)則,篩選氣動結(jié)構(gòu)；對合理的氣動結(jié)構(gòu)進行成型,通過三維數(shù)值模擬分析其整體性能和流動狀況,并作進一步優(yōu)化。 本文采用三維時均Navier-Stokes方程,并結(jié)合RNG k-ε湍流模型,對離心風(fēng)機內(nèi)部流場進行了數(shù)值模擬。數(shù)值模擬的計算結(jié)果和實驗數(shù)據(jù)十分吻合,并很好的預(yù)測了離心風(fēng)機的全壓和效率曲線。通過數(shù)值模擬,本文比較了不同設(shè)計模型和原始機型的性能和流動特征。相比于原始機型,最優(yōu)設(shè)計模型的效率平均提升5%左右,風(fēng)機流場內(nèi)的分離流動、二次流、射流-尾流均有減弱。本文詳細的分析了風(fēng)機各部分的流動以及不同工況條件下葉輪流道內(nèi)速度和壓力的分布情況,并捕捉到了風(fēng)機流場內(nèi)的分離流動、二次流、射流-尾流等流動特征。葉輪損失是整個風(fēng)機的損失的最主要來源,約占總損失的1/2,而蝸殼部分的損失則占據(jù)了剩余損失的絕大部分。葉輪子午平面初始段,前盤表面聚集了低速流體,從而引起了整個流道內(nèi)流動的不穩(wěn)定,隨著流量的增加,這種不穩(wěn)定性越來越強烈。同時,由于葉輪和蝸殼的相互作用,在蝸殼內(nèi)形成了二次流和環(huán)流。在幾乎所有的葉輪流道出口附近,都存在典型的射流—尾流結(jié)構(gòu)。由于旋轉(zhuǎn)和曲率的影響,葉輪流道內(nèi)的二次流較為顯著。最后,本文還分析了風(fēng)機進風(fēng)口和葉輪之間的間隙流動,該流動對風(fēng)機的整體性能有著顯著的影響。
[Abstract]:Because of its high output pressure, the forward centrifugal fan, such as 9-1999-26 series, is widely used in material transportation, forging furnace and high pressure forced ventilation. Compared with the backward fan, the forward fan has lower efficiency and higher noise. In this paper, aiming at the forward centrifugal fan and taking the 9-19 fan as the design example, the forward blade is redesigned into the backward blade by a reasonable aerodynamic design method. The numerical simulation method is used to analyze and optimize the fan so as to improve the efficiency of the fan under the condition of satisfying the flow rate and pressure. The design idea of this paper is based on the flow characteristics in the impeller passage of centrifugal fan, starting from the velocity distribution in the impeller passage, controlling the growth of the boundary layer, separating the boundary layer of suction edge, delaminating effect and secondary flow, so as to weaken the wake zone. The purpose of reducing the flow loss is to make the design method in this paper more suitable for the actual flow condition than the traditional method. The main step of aerodynamic design is to design the geometric shape of the impeller by controlling the distribution of the average relative velocity in the impeller. A series of objective functions and design criteria are adopted to screen the pneumatic structure, and the reasonable aerodynamic structure is formed, and its overall performance and flow state are analyzed by three-dimensional numerical simulation, and further optimized. In this paper, the three-dimensional time-averaged Navier-Stokes equation and the RNG k- 蔚 turbulence model are used to simulate the flow field in the centrifugal fan. The results of the numerical simulation are in good agreement with the experimental data. Through numerical simulation, the performance and flow characteristics of different design models and original models are compared. Compared with the original model, the efficiency of the optimal design model is increased by about 5% on average. The separation flow, secondary flow and jet-wake flow in the fan flow field are all weakened. This paper analyzes in detail the flow in various parts of the fan and the distribution of velocity and pressure in the impeller passage under different working conditions. The separation flow, secondary flow, jet-wake flow and other flow characteristics in the fan flow field are captured. The impeller loss is the main source of the loss of the whole fan. About 1 / 2 of the total loss, while the volute part of the loss accounts for the majority of the remaining loss. In the initial section of the impeller meridian plane, a low velocity fluid accumulates on the front surface of the impeller, thus causing instability of the flow in the entire channel, and with the increase of the flow rate, At the same time, because of the interaction between the impeller and the volute, secondary flow and circulation are formed in the volute. Because of the influence of rotation and curvature, the secondary flow in the impeller passage is obvious. Finally, the gap flow between the fan inlet and the impeller is analyzed. The flow has a significant impact on the overall performance of the fan.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2011
【分類號】：TH432

【參考文獻】

相關(guān)期刊論文 前10條

1 徐長棱,毛義軍,李凱 ,譚佳建;離心通風(fēng)機整機三維流場的數(shù)值模擬[J];風(fēng)機技術(shù);2005年05期

2 黃利忠;竇勇;李嵩;黃東濤;;特小比轉(zhuǎn)數(shù)的后向離心通風(fēng)機的研究與開發(fā)[J];風(fēng)機技術(shù);2006年04期

3 王曉鋒,席光,王尚錦;響應(yīng)面方法在葉片擴壓器優(yōu)化設(shè)計中的應(yīng)用研究[J];工程熱物理學(xué)報;2003年03期

4 王嘉冰,區(qū)穎達,吳克啟;空調(diào)風(fēng)機葉道內(nèi)旋渦流動分析及進氣口偏心的影響[J];工程熱物理學(xué)報;2005年06期

5 李景銀;田華;牛子寧;;葉片開縫的離心風(fēng)機流場研究[J];工程熱物理學(xué)報;2009年12期

6 呂峰;牛子寧;李景銀;;離心風(fēng)機蝸殼內(nèi)部流動研究[J];流體機械;2009年06期

7 沈天耀;前向葉輪的流動模型及其設(shè)計計算方法[J];清華大學(xué)學(xué)報(自然科學(xué)版);1980年02期

8 劉曉良;袁民建;毛義軍;祁大同;;前向離心風(fēng)機蝸殼出口結(jié)構(gòu)的數(shù)值優(yōu)化[J];西安交通大學(xué)學(xué)報;2009年05期

9 毛義軍;祁大同;徐長棱;劉秋洪;;葉片與蝸舌耦合對離心風(fēng)機性能和旋轉(zhuǎn)噪聲影響的數(shù)值研究[J];應(yīng)用力學(xué)學(xué)報;2006年03期

10 祁大同，李占良;離心風(fēng)機葉片型線的一種二維逆命題簡便設(shè)計方法[J];應(yīng)用力學(xué)學(xué)報;1994年03期

，

本文編號：1597871