本文選題：比轉數(shù) + 葉片型線��； 參考：《上海交通大學》2012年碩士論文

【摘要】：現(xiàn)有的熱泵系統(tǒng)主要應用于食品加工、化纖制造和木材加工等行業(yè)的干燥循環(huán)系統(tǒng),而超低比轉數(shù)離心鼓風機是該系統(tǒng)最關鍵的設備之一。該類風機的特點是小流量高壓升,這種氣動特性決定了其極低的比轉數(shù)。因此該類風機設計時只能采用窄葉輪結構,這就使得其內部的壁面粘性效應和流動分離現(xiàn)象顯著,引起的流動損失將遠大于正常葉輪寬度風機的損失,因此導致實際應用中效率往往低于傳統(tǒng)風機。該類鼓風機應用廣泛并且必須長年不間斷地運行,加上實際應用效率較低,使其耗能巨大,因此提高其性能對節(jié)能環(huán)保有著重要的現(xiàn)實意義。 對于離心風機,影響葉輪性能的因素有葉片型線以及葉輪寬度等。當葉片進口安裝角一定時,葉片形狀影響整個流道內的壓力和速度分布,而壓力速度的分布勢必影響葉輪的性能。因此研究不同葉片型線葉輪及不同寬度葉輪內部的流動情況,探索葉輪內流場的流動機理,對于提高其性能具有重要的作用。因此本文將主要研究焦點定位于葉片型線和葉輪寬度對超低比轉數(shù)離心鼓風機性能的影響。 本文根據(jù)工程中現(xiàn)有應用比較廣泛的某一超低比轉數(shù)離心鼓風機,設計了一個具有同樣流量系數(shù)和壓升系數(shù)的風機模型進行研究。在一定的參數(shù)下設計了3種不同型線的葉片,即前彎葉片、后彎葉片和變厚度前彎葉片。 首先本文對3種葉型葉輪進行性能實驗研究,測得了3種葉輪分別在4個轉速下的10個流量工況的性能數(shù)據(jù),并通過相似原理進行曲線擬合,得到了3種葉片的性能曲線。以此為依據(jù),分析了3種不同型線葉片的性能差異。結果顯示楔形葉片在3種葉片中具有相對較好的性能,而傳統(tǒng)風機常使用的后彎葉片的性能并不占優(yōu)。為了進一步分析葉片型線對超低比轉數(shù)離心鼓風機產生性能差異的原因,本文又對3種葉輪進行可視化流動實驗。在流道中均勻分布7組示蹤排線,通過示蹤排線的指示方向來判斷當?shù)匚恢脷饬鞯姆较?借助對葉輪流道內部氣流直觀的流動觀察來分析葉片型線對流道內部氣流的影響情況,以此來部分解釋性能差異的原因。 由于可視化流動實驗條件的限制,并不能獲得完整的流場信息。因此本文對離心鼓風機模型進行全三維整機CFD計算,通過對風機內部流場的模擬來深入的分析不同葉片型線風機產生性能差異的機理。結果顯示后彎葉片的受到的壁面的粘性效應和分離現(xiàn)象顯著,由此產生的回流現(xiàn)象明顯;楔形葉片在前彎葉片的基礎上通過優(yōu)化得到,在一定程度上改善了由于葉輪流道過窄而產生的流動分離效應,使該類風機具有較好的效率。 通過對不同葉片型線的葉輪進行研究發(fā)現(xiàn)通過改變葉片型線僅在一定程度上改善了由于葉輪流道過窄而產生的粘性效應增強和流動分離現(xiàn)象。由此可見葉輪寬度對該類風機的性能具有很大的影響。本文進一步又對不同寬度的葉輪進行數(shù)值研究。改變葉輪寬度可能導致出口流量和壓升產生一定的變化,從而偏離設計工況。因此,可以尋求一個合適的葉輪寬度,使得該風機在一定的設計工況偏離值內獲得最優(yōu)的總體性能。
[Abstract]:The existing heat pump system is mainly used in food processing, circulation system of dry chemical fiber manufacturing and wood processing industries, and super low specific speed centrifugal blower is one of the most important equipment in the system. The blower has the characteristic of small flow and high pressure rise, the aerodynamic characteristics determine its very low specific speed. Therefore the design of this kind of fan only by narrow impeller structure, which makes the internal wall viscous effect and flow separation phenomenon significantly, flow caused by the loss will be greater than the normal fan impeller width loss, therefore leads to the actual application efficiency is often lower than the traditional blower. The blower is widely used and not for many years continuous operation, and the actual application efficiency is low, the energy consumption is huge, so improve its performance has important practical significance to energy saving and environmental protection.
For the centrifugal fan, factors affecting the performance of the impeller blade and impeller width. When the blade installation angle when the influence of the pressure and velocity distribution of the whole passage shape of the blade, and the pressure and velocity distribution of impeller is bound to affect the performance. Therefore research on the internal flow of different leaf types and different line width of impeller the impeller, exploring of impeller flow mechanism, plays an important role in improving the performance. So this paper will mainly focus on the profile of the blade and impeller width on the ultra-low specific speed centrifugal blower.
According to a comparison of a wide range of existing application of low specific speed centrifugal blower, a design with the same flow coefficient and pressure coefficient of the wind turbine model is studied. With certain parameters designed 3 different blade profile, the blade, blade and variable thickness after bending before curved blade.
Firstly, experiments were carried out to study the performance of 3 kinds of blade impeller, the performance data measured 3 kinds of impeller in 4 speed under 10 flow conditions, and the curve fitting by similarity principle, the performance curves of the 3 leaves. On this basis, analyzes the differences between the performance of 3 different type linearifolia tablets the results showed that with relatively good performance in the 3 wedge blade in the blade and blade often uses the traditional performance of the fan is not dominant. In order to further analyze the blade profile of super low specific speed centrifugal blower performance difference, for the flow visualization experiment of 3 kinds of impeller 7. Group tracing distribution cable in the flow passage, through the direction of tracing cable to determine the local position of the direction of air flow, the flow of air flow in the impeller visual observation to analyze the blade profile of the internal gas flow The influence of the flow is explained in part to explain the reasons for the difference in performance.
Because the condition of flow visualization experiment limit, and can not get the information flow integrity. The centrifugal blower model full 3D machine CFD calculation, through the simulation of the internal flow field of the fan blade type line to in-depth analysis of different wind turbine performance difference mechanism. The results show significant blade by the wall the effect of viscosity and separation, resulting reflux is obvious; wedge blade optimization based on the obtained by curved blades, is improved to a certain extent due to narrow impeller flow separation effect, so the blower has better efficiency.
Study found that the viscous effect by changing the blade type line only improved to a certain extent due to narrow impeller enhancement and flow separation phenomenon through the impeller of different blade type line. Thus the impeller width has great influence on the performance of the fan. The paper further on the different width of the impeller was numerically study. Different impeller width may lead to outlet flow and pressure change to deviate from the design condition. Therefore, you can look for a suitable impeller width, the fan in the design condition certain deviation from the best overall performance value.

【學位授予單位】：上海交通大學
【學位級別】：碩士
【學位授予年份】：2012
【分類號】：TH442

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