【摘要】：本文對(duì)牛頓特性血液流體、非牛頓特性血液流體在人體肺動(dòng)脈及其分支內(nèi)的血流動(dòng)力學(xué)特性進(jìn)行了數(shù)值模擬,并使用有限元方法對(duì)血液與血管的流固耦合問題進(jìn)行了模擬研究。 本文首先建立90°彎管模型,假定血液為牛頓流體,對(duì)彎管內(nèi)血液動(dòng)力學(xué)環(huán)境進(jìn)行數(shù)值模擬,并將模擬結(jié)果與實(shí)驗(yàn)數(shù)據(jù)進(jìn)行對(duì)比,發(fā)現(xiàn)兩者具有較好的吻合性,證明擬采用的數(shù)值方法能夠比較真實(shí)的模擬血管內(nèi)血液的流動(dòng)情況。進(jìn)而采用Womersley脈動(dòng)速度入口條件,對(duì)重建后的肺動(dòng)脈及其分支,在一個(gè)心動(dòng)周期內(nèi)的牛頓脈動(dòng)流血流動(dòng)力學(xué)環(huán)境進(jìn)行了數(shù)值模擬研究。 然后,同樣建立90°彎管模型對(duì)非牛頓特性血液流進(jìn)行數(shù)值模擬,驗(yàn)證數(shù)值方法的適用性�？紤]血液的非牛頓特性,將carreau模型應(yīng)用到控制方程中,求解了肺動(dòng)脈及其分支的血液動(dòng)力學(xué)參數(shù)。 研究表明,正常成人在心臟收縮期,主肺動(dòng)脈及左、右肺動(dòng)脈分支的壓力均較心臟舒張期高；右肺動(dòng)脈壓力明顯高于左肺動(dòng)脈,右葉間動(dòng)脈壓力較左側(cè)高；主肺動(dòng)脈及左、右肺動(dòng)脈內(nèi)的流速有顯著性差異,右肺動(dòng)脈遠(yuǎn)端流速遠(yuǎn)大于左肺動(dòng)脈；在收縮期右肺動(dòng)脈分叉前近端血流形成高壁面剪切力場(chǎng)。由此可見,右肺動(dòng)脈近端和右葉間動(dòng)脈是血液動(dòng)力學(xué)參數(shù)最早出現(xiàn)改變的階段,對(duì)于早期肺動(dòng)脈高壓的診斷,應(yīng)著眼于此段動(dòng)脈的形態(tài)及功能改變。另外,本文將牛頓特性血液流體與非牛頓特性血液流體數(shù)值模擬結(jié)果進(jìn)行對(duì)比,結(jié)果顯示,牛頓流體與非牛頓流體模擬結(jié)果數(shù)值上存在差異,但動(dòng)脈內(nèi)速度、壓力以及壁面剪切力分布的輪廓基本一致。 最后,建立基于真實(shí)人體肺動(dòng)脈的三維分叉結(jié)構(gòu),研究血液與彈性壁流固耦合問題,對(duì)血管的變形情況、血流的動(dòng)力學(xué)特性進(jìn)行了數(shù)值模擬。結(jié)果顯示,在等效應(yīng)力最大處,變形也最大,符合生理規(guī)律。肺動(dòng)脈出入口以及分叉處是整個(gè)心動(dòng)周期內(nèi)流速、壓力以及壁面剪切力變化最活躍的位置,也是整個(gè)心動(dòng)周期內(nèi)壓力、流速和最高剪切力出現(xiàn)的位置,所以肺動(dòng)脈出入口,以及分叉處是發(fā)生病變的最初位置。
[Abstract]:In this paper, the hemodynamic characteristics of Newtonian blood fluid and non-Newtonian blood fluid in human pulmonary artery and its branches are numerically simulated, and the fluid-solid coupling between blood and blood vessel is studied by finite element method. In this paper, a 90 擄curved pipe model is established. The hemodynamic environment in the bend is numerically simulated on the assumption that the blood is Newtonian fluid, and the simulation results are compared with the experimental data. It is found that the two models are in good agreement with each other. It is proved that the proposed numerical method can simulate the flow of blood in blood vessels. Then the dynamic environment of Newtonian pulsating blood flow in a cardiac cycle was numerically simulated by using the Womersley pulsation velocity inlet condition for the reconstructed pulmonary artery and its branches. Then, the 90 擄bend model is also established to simulate the non-Newtonian characteristic blood flow, which verifies the applicability of the numerical method. Considering the non-Newtonian characteristics of blood, the carreau model is applied to the governing equation, and the hemodynamic parameters of the pulmonary artery and its branches are solved. Studies have shown that the pressure of the main pulmonary artery and the branches of the left and right pulmonary arteries in normal adults is higher than that in the diastolic period, the pressure of the right pulmonary artery is significantly higher than that of the left pulmonary artery, the pressure of the right interlobar artery is higher than that of the left, the pressure of the main pulmonary artery and the left pulmonary artery, The velocity in the right pulmonary artery was significantly different, the velocity of the distal right pulmonary artery was much larger than that of the left pulmonary artery, and a high wall shear force field was formed at the proximal end of the right pulmonary artery bifurcation in the systolic phase. It can be seen that the proximal right pulmonary artery and the right interlobar artery are the earliest changes in hemodynamic parameters. For the diagnosis of early pulmonary hypertension, we should focus on the morphological and functional changes of this segment of artery. In addition, the numerical simulation results of Newtonian blood fluid and non-Newtonian blood fluid are compared. The results show that the numerical value of Newtonian fluid and non-Newtonian fluid is different, but the velocity of artery is different. The profile of pressure and wall shear force distribution is basically the same. Finally, a three-dimensional bifurcation structure based on real human pulmonary artery is established to study the fluid-solid coupling between blood and elastic wall. The deformation of blood vessels and the dynamic characteristics of blood flow are numerically simulated. The results show that the deformation is the largest at the maximum equivalent stress, which accords with the physiological law. The entrance and exit of the pulmonary artery and the bifurcation are the most active sites for the changes of velocity, pressure and wall shear force throughout the cardiac cycle, and also the location where the pressure, velocity and maximum shear force appear throughout the cardiac cycle, so the pulmonary artery entrance and exit. And the bifurcation is the initial location of the lesion.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2011
【分類號(hào)】：R312

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