本文選題：超臨界 + 噴霧　； 參考：《大連理工大學(xué)》2015年碩士論文

【摘要】：本文以內(nèi)燃機(jī)環(huán)境下燃料的超臨界噴射為研究對(duì)象,著重考察燃料噴霧在超臨界工況下的發(fā)展過程、實(shí)際氣體狀態(tài)方程Soave-Redlich-Kwong (SRK)和 Peng-Robinson(PR)兩個(gè)方程對(duì)超臨界工況的適用性、以及氣液混合層的可能位置及其演化特性。針對(duì)Sandia實(shí)驗(yàn)室關(guān)于正庚烷噴霧的實(shí)驗(yàn)數(shù)據(jù)(www.sandia.gov/ecn),基于Converge軟件采用大渦模擬即LES (Large eddy simulation)和雷諾平均(RANS)方法對(duì)以正庚烷為燃料噴入超臨界環(huán)境中的霧化過程進(jìn)行了數(shù)值模擬。以實(shí)際氣體狀態(tài)方程SRK和PR方程為基礎(chǔ),重點(diǎn)研究了LES和RANS下兩狀態(tài)方程對(duì)超臨界狀態(tài)下燃料噴霧的正庚烷的質(zhì)量分?jǐn)?shù)、溫度分布的影響；LES下燃料噴霧的質(zhì)量分?jǐn)?shù)隨溫度變化,并與實(shí)驗(yàn)結(jié)果進(jìn)行對(duì)比；以及LES下的射流密度變化、密度梯度變化和蒸汽的質(zhì)量分?jǐn)?shù)等值線的分布。結(jié)果表明,LES下兩狀態(tài)方程計(jì)算的正庚烷的質(zhì)量分?jǐn)?shù)和溫度分布有著很大的區(qū)別,而RANS方法下兩者得到的結(jié)果區(qū)別很�。煌粫r(shí)間下PR方程模擬的燃料噴霧的貫穿距更大,但是SRK方程模擬的噴霧前端的渦狀出現(xiàn)的更早；兩狀態(tài)方程下射流表面都有大的密度梯度；燃料質(zhì)量分?jǐn)?shù)隨溫度的變化符合實(shí)際的情況。通過本文研究得出了以下的結(jié)論：RANS模型不太適用于內(nèi)燃機(jī)噴霧湍流模擬；LES下的正庚烷的質(zhì)量分?jǐn)?shù)、溫度、密度分布相互印證了正庚烷的質(zhì)量分?jǐn)?shù)在軸向和徑向都是隨著距離的增大而逐漸減��；PR方程對(duì)于超臨界工況的計(jì)算可能更優(yōu)于SRK方程；密度值的急劇變化驗(yàn)證了射流表面存在一個(gè)介于液體與氣體之間的混合層；可以通過大密度梯度的位置來推測(cè)混合層的可能位置,混合層隨著軸向距離的增大而向外移動(dòng)；蒸汽的質(zhì)量分?jǐn)?shù)等值線圖也印證之前得出的正庚烷的質(zhì)量分?jǐn)?shù)的變化情況。
[Abstract]:In this paper, the supercritical injection of fuel in the environment of internal combustion engine is taken as the research object, and the development process of fuel spray under supercritical condition is emphatically investigated. The applicability of the actual gas equation of state Soave-Redlich-Kwong SSRK and Peng-Robinsonian PR) to the supercritical condition is investigated. And the possible location and evolution characteristics of the gas-liquid mixed layer. Based on the experimental data of Sandia laboratory on n-heptane spray (www.sandia.gov-ecng), the atomization process of n-heptane injection into supercritical environment was numerically simulated by means of large eddy simulation (les large eddy simulation) and Reynolds average rags (RANSs) method based on converge software. Based on the actual gas state equations SRK and PR, the effects of the two equations of state under les and rans on the mass fraction of n-heptane in supercritical state and the effect of temperature distribution on the mass fraction of fuel spray under les are studied. The results are compared with the experimental results, and the distribution of jet density, density gradient and the contours of steam mass fraction under les. The results show that the mass fraction and temperature distribution of n-heptane calculated by the two equations of state are very different from those obtained by rans method, and the penetration distance of fuel spray simulated by PR equation at the same time is larger than that obtained by rans method. But the vortex of the spray front end simulated by SRK equation appears earlier; the jet surface has a large density gradient under the two equation of state; the change of fuel mass fraction with temperature is in line with the actual situation. The following conclusions are obtained from the study in this paper: the 1: rans model is not suitable for the mass fraction and temperature of n-heptane in the spray turbulence simulation of internal combustion engine under les. The density distribution verifies that the mass fraction of n-heptane decreases gradually with the increase of distance in axial and radial direction, and the PR equation may be better than SRK equation in supercritical condition. The sharp change of density value verifies the existence of a mixing layer between liquid and gas on the surface of the jet, and the possible position of the mixing layer can be inferred by the position of large density gradient, and the mixing layer moves outward with the increase of axial distance. The isogram of steam mass fraction also confirms the change of n-heptane mass fraction.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TK407.9

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本文編號(hào)：1992762