本文選題：液力變矩器 + 導(dǎo)輪結(jié)構(gòu)��； 參考：《吉林大學(xué)》2011年碩士論文

【摘要】：液力變矩器是自動變速器的重要部件之一,其結(jié)構(gòu)形式和性能對轎車的經(jīng)濟(jì)性和動力性有很大影響。對于發(fā)動機(jī)前置的轎車,由于空間結(jié)構(gòu)的限制,液力變矩器向著扁平化方向發(fā)展以減小軸向尺寸。導(dǎo)輪結(jié)構(gòu)對于改變液力變矩器的軸向尺寸有著重要影響,同時會對液力變矩器的性能產(chǎn)生影響。研究導(dǎo)輪結(jié)構(gòu)形式對液力變矩器性能的影響,目的在于找到適合的導(dǎo)輪結(jié)構(gòu),提高液力變矩器的性能。文中分別設(shè)計了兩種具有不同導(dǎo)輪結(jié)構(gòu)形式的扁平化液力變矩器循環(huán)圓,并對兩個液力變矩器各葉輪葉片進(jìn)行了設(shè)計,建立了兩個液力變矩器的流道模型及網(wǎng)格模型,應(yīng)用CFD軟件對液力變矩器內(nèi)部流動進(jìn)行數(shù)值模擬,計算出內(nèi)部三維流動分布和外部性能。通過對不同導(dǎo)輪結(jié)構(gòu)的液力變矩器內(nèi)部流動狀態(tài)的分析和性能的對比,得到導(dǎo)輪結(jié)構(gòu)形式對內(nèi)部流動和外部性能的影響規(guī)律。針對兩個不同導(dǎo)輪結(jié)構(gòu)形式的液力變矩器性能的優(yōu)劣,提出轎車扁平化液力變矩器優(yōu)化方法,以提高轎車扁平化液力變矩器的性能。主要研究內(nèi)容如下： (1)設(shè)計扁平率為0.8的兩個扁平化液力變矩器。 首先,設(shè)計兩個扁平化液力變矩器的循環(huán)圓。文中采用基于橢圓的循環(huán)圓設(shè)計方法,設(shè)計扁平率為0.8的液力變矩器循環(huán)圓。為對比分析導(dǎo)輪結(jié)構(gòu)形式對液力變矩器性能的影響,兩個液力變矩器泵輪和渦輪的循環(huán)圓形狀對應(yīng)相同,導(dǎo)輪循環(huán)圓采用常用的兩種結(jié)構(gòu)形式,即直線導(dǎo)輪和圓弧導(dǎo)輪結(jié)構(gòu)。 其次,設(shè)計各葉輪的葉片。文中各葉輪的葉片均采用環(huán)量分配法進(jìn)行設(shè)計。兩個液力變矩器中的泵輪、渦輪和導(dǎo)輪分別采用相同的二次函數(shù)環(huán)量分配規(guī)律進(jìn)行設(shè)計。 最后,建立兩個液力變矩器的計算模型并進(jìn)行數(shù)值模擬。抽取兩個液力變矩器的流道模型,并應(yīng)用CFD軟件對全流道進(jìn)行網(wǎng)格劃分,將整體網(wǎng)格模型導(dǎo)入CFD軟件,選擇滑動網(wǎng)格法進(jìn)行數(shù)值模擬,湍流模型選用標(biāo)準(zhǔn)κ-ε模型,設(shè)定邊界條件,采用SIMPLE算法的分離式求解法進(jìn)行數(shù)值模擬。 (2)不同導(dǎo)輪結(jié)構(gòu)形式的兩個液力變矩器瞬態(tài)流場分析。 對比兩個液力變矩器的內(nèi)部流動,主要是典型工況時流道的整體壓力分布和速度分布。 兩個扁平化液力變矩器在起動工況和最高效率工況的壓力和速度分布規(guī)律一致。起動工況時液力變矩器的循環(huán)流量最大,渦輪轉(zhuǎn)速為零,泵輪出口處的壓力和速度高于入口處,而渦輪則相反,導(dǎo)輪流道中壓力和速度變化較小,受離心力及Coriolis的作用,外環(huán)壓力和速度高于內(nèi)環(huán)。與起動工況相比,最高效率工況的壓力分布較為均勻,這是因為最高效率工況時渦輪和泵輪轉(zhuǎn)速差較小,葉輪間能量交換較少,這時的離心力較大,流道外環(huán)壓力明顯高于內(nèi)環(huán)壓力。 由于導(dǎo)輪結(jié)構(gòu)形式不同,兩個液力變矩器流場的壓力和速度分布存在一些差別。在起動工況,圓弧導(dǎo)輪扁平化液力變矩器流道整體壓力高于直線導(dǎo)輪扁平化液力變矩器,逆壓區(qū)范圍較小,泵輪出口渦輪入口處速度略低,導(dǎo)輪流道速度較高。在最高效率工況,圓弧導(dǎo)輪扁平化液力變矩器整體壓力分布更為均勻,壓力和速度都較高。 (3)對比分析了導(dǎo)輪結(jié)構(gòu)形式對轎車扁平化液力變矩器性能的影響。 轉(zhuǎn)速比i0.8時,圓弧導(dǎo)輪扁平化液力變矩器的效率高于直線導(dǎo)輪扁平化液力變矩器,i≥0.8時,兩個扁平化液力變矩器效率值近似相等。與效率的分布規(guī)律相同,轉(zhuǎn)速比i0.8時圓弧導(dǎo)輪扁平化液力變矩器的變矩比較大,轉(zhuǎn)速比i≥0.8時,兩個液力變矩器的轉(zhuǎn)矩比近似相等。對比兩個液力變矩器的泵輪容量系數(shù)和循環(huán)流量可以看出,圓弧導(dǎo)輪扁平化液力變矩器的泵輪容量系數(shù)較大,循環(huán)流量較小。 (4)對轎車扁平化液力變矩器進(jìn)行優(yōu)化。針對具有兩個不同導(dǎo)輪結(jié)構(gòu)形式的扁平化液力變矩器性能的優(yōu)劣,在圓弧導(dǎo)輪液力變矩器的基礎(chǔ)上設(shè)計一種新的液力變矩器,具體方法就是減小圓弧導(dǎo)輪的軸向尺寸,其他結(jié)構(gòu)保持不變,采用相同的方法進(jìn)行CFD仿真分析,對比寬窄兩種導(dǎo)輪的扁平化液力變矩器的性能。對比可以看出,寬導(dǎo)輪扁平化液力變矩器泵輪轉(zhuǎn)矩系數(shù)高和循環(huán)流量低的狀況得到改善,達(dá)到了性能優(yōu)化的目的。 綜上所述,本文設(shè)計了具有兩種常用導(dǎo)輪結(jié)構(gòu)形式的液力變矩器,通過對兩個液力變矩器內(nèi)部流場的仿真分析,得到了導(dǎo)輪結(jié)構(gòu)形式對扁平化液力變矩器內(nèi)部流動及外部性能的影響規(guī)律,并通過改變導(dǎo)輪軸向長度,使液力變矩器的性能得到優(yōu)化。
[Abstract]:The hydraulic torque converter is one of the important parts of automatic transmission , its structure and performance have great influence on the economy and power of the car .


( 1 ) Two flat hydraulic torque converters with a flat rate of 0.8 are designed .


Firstly , the circular circle of two flat hydraulic torque converter is designed . The circular circle of hydraulic torque converter with the flat rate of 0.8 is designed by the circular design method based on the ellipse . In order to analyze the effect of the guide wheel structure on the performance of the torque converter , the circular shapes of the two torque converter pump wheels and the turbine are the same , and the circular circle of the guide wheel adopts the common two structural forms , namely , the linear guide wheel and the circular arc guide wheel structure .


secondly , the blades of each impeller are designed ; the blades of each impeller are designed by adopting a ring quantity distribution method ; and the pump wheel , the turbine and the guide wheel in the two hydraulic torque converter are respectively designed by adopting the same quadratic function ring quantity distribution law .


At last , the calculation model of two torque converter is established and the numerical simulation is carried out . The flow path model of two torque converter is extracted , and the whole flow channel is divided by CFD software , the integral mesh model is introduced into CFD software , the sliding grid method is selected for numerical simulation , the turbulent model selects the standard kappa - 蔚 model , the boundary condition is set , and the numerical simulation is carried out by using the separated solution method of SIMPLE algorithm .


( 2 ) Transient flow field analysis of two hydraulic torque converter in different wheel structure forms .


The internal flow of two torque converter is compared , which is mainly the overall pressure distribution and velocity distribution of the runner during typical operating conditions .


Compared with the starting working condition , the pressure and velocity of the turbine and the pump impeller are smaller , the pressure and the speed of the outer ring are higher than the inner ring .


Due to the different forms of the guide wheel structure , there are some differences between the pressure and the velocity distribution of the flow field of the two hydraulic torque converter . In the starting condition , the integral pressure of the arc guide wheel flat hydraulic torque converter is higher than that of the linear guide wheel flat hydraulic torque converter , the range of the reverse pressure area is small , the speed of the inlet of the pump wheel outlet turbine is slightly lower , and the rotation speed is higher . Under the maximum efficiency condition , the integral pressure distribution of the circular arc guide wheel flat hydraulic torque converter is more uniform , and the pressure and the speed are higher .


( 3 ) The effect of guide wheel structure on the performance of flat hydraulic torque converter is analyzed .


When the speed ratio is higher than that of the linear guide wheel flat hydraulic torque converter , the torque ratio of the two hydraulic torque converter is approximately equal . When the speed ratio is more than or equal to 0.8 , the torque ratio of the two hydraulic torque converter is approximately equal . Compared with the pump wheel capacity coefficient and the circulating flow rate of the two torque converter , it can be seen that the capacity coefficient of the pump wheel of the circular arc guide wheel flat hydraulic torque converter is large , and the circulation flow is small .


( 4 ) To optimize the torque converter of the flat hydraulic torque converter with two different guide wheels , a new torque converter is designed on the basis of the arc guide wheel hydraulic torque converter . The method is to reduce the axial dimension of the circular arc guide wheel , the other structure remains the same , and the performance of the flat hydraulic torque converter with the same method is compared .


In conclusion , the hydraulic torque converter with two kinds of common guide wheel structures is designed in this paper . Through the simulation analysis of the internal flow field of the two hydraulic torque converter , the influence law of the guide wheel structure on the internal flow and external performance of the flat hydraulic torque converter is obtained , and the performance of the torque converter is optimized by changing the axial length of the guide wheel .
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2011
【分類號】：TH137.332

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