【摘要】：功率超聲珩磨加工過程中,磨削區(qū)常有大量空化泡產(chǎn)生,它們會快速膨脹、壓縮直至崩潰,并在崩潰瞬間產(chǎn)生高溫高壓等現(xiàn)象。為了探討其對超聲珩磨加工過程的影響,本文對其動力學(xué)行為及潰滅特性進行了研究。 首先以磨削液為液體介質(zhì),研究了超聲振動珩磨環(huán)境下單個氣泡的動力學(xué)特性。將氣泡大于初始半徑的運動過程看作是等溫過程,而氣泡小于初始半徑的運動過程看作是絕熱過程,建立了動力學(xué)模型,并運用MATLAB軟件中的4-5階Runge-Kutta進行求解,探討了各影響因素對其運動規(guī)律的影響。研究發(fā)現(xiàn),超聲珩磨磨削區(qū)空化泡的運動較穩(wěn)定,但頻率較快、振幅較小。珩磨壓力對空化泡運動規(guī)律影響較大,對空化泡潰滅過程有促進的作用。而回轉(zhuǎn)速度、往復(fù)速度的影響則相對較小。磨削液的粘滯系數(shù)越大,空化泡的振幅越小。環(huán)境溫度的升高會使得較小的空化泡運動幅度更加劇烈,而較大的空化泡會逐漸變得平穩(wěn)。聲壓幅值對空化泡運動規(guī)律的影響也比較大,當(dāng)PαPo+PH時,空化很難發(fā)生,當(dāng)Pα≥Po+PH時,隨著聲壓幅值的增加,空化泡的振幅會明顯變大,且更易于被壓潰,空化程度更加劇烈。 然后針對磨削區(qū)單空泡建立并求解了空泡潰滅瞬間的最大溫度、壓強公式,運用MATLAB軟件分析了各因素對潰滅溫度、壓強的影響。結(jié)果表明：超聲珩磨磨削區(qū)空化泡潰滅瞬間的最大溫度Tmax、最大壓力Pmax比普通超聲空化的要大,但隨著環(huán)境溫度的升高二者差距會逐漸減小。Tmax、Pmax會隨著珩磨壓力、聲壓幅值的增大明顯增大,隨著環(huán)境溫度的升高迅速減小,雖然也會隨珩磨頭回轉(zhuǎn)速度及往復(fù)速度的增大有所增大,但增幅較小。 最后建立了超聲珩磨環(huán)境中單空化泡CFD幾何模型,結(jié)合己經(jīng)得到單空泡潰滅瞬間產(chǎn)生的高溫,運用FLUENT軟件對其擴散過程進行了分析。發(fā)現(xiàn)空化泡潰滅瞬間產(chǎn)生的高溫會先傳遞給磨削液,并隨著磨削液的流動快速傳遞給工件和油石,所選研究對象系統(tǒng)溫度隨著潰滅溫度的擴散會提升1-2K�？栈轁缢a(chǎn)生的高溫區(qū)域會隨著磨削液的流動而改變位置，并使得工件表面存在瞬時高溫，，影響超聲珩磨加工。
[Abstract]:In the process of power ultrasonic honing, a large number of cavitation bubbles often occur in the grinding area, which will expand rapidly, compress to collapse, and produce high temperature and high pressure at the moment of collapse. In order to study the effect of ultrasonic honing on the process of ultrasonic honing, the dynamic behavior and collapsing characteristics of ultrasonic honing were studied in this paper. Firstly, the dynamic characteristics of single bubble in ultrasonic vibration honing environment were studied with grinding fluid as liquid medium. The motion process of bubble larger than initial radius is regarded as isothermal process, while that of bubble less than initial radius is regarded as adiabatic process. The dynamic model is established and solved by using 4-5 order Runge-Kutta in MATLAB software. The influence of various factors on its motion law is discussed. It is found that the cavitation bubble in the grinding area of ultrasonic honing is stable, but the frequency is faster and the amplitude is smaller. Honing pressure has great influence on cavitation bubble motion and promotes cavitation bubble collapse process. However, the influence of rotation velocity and reciprocating velocity is relatively small. The larger the viscosity coefficient of grinding fluid, the smaller the amplitude of cavitation bubble. The increase of ambient temperature will make the smaller cavitation bubble motion more intense, and the larger cavitation bubble will gradually become stable. The effect of sound pressure amplitude on cavitation bubble motion is also relatively large. When P 偽 Po PH, cavitation is very difficult to occur. When P 偽 鈮

本文編號：2284178