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柴油機(jī)漸縮形噴孔噴嘴流動(dòng)特性研究
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國家自然科學(xué)基金資助項(xiàng)目(51176068)、江蘇高校優(yōu)勢學(xué)科建設(shè)工程資助項(xiàng)目和江蘇省博士創(chuàng)新基金資助項(xiàng)目(CXZZ12_0674)


Flow Characteristics in Diesel Nozzle with Convergent Conical Orifice
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    摘要:

    利用混合多相流空穴模型,對柴油機(jī)漸縮形噴孔噴嘴進(jìn)行了三維氣液兩相流數(shù)值模擬,分析了噴油壓力、噴油背壓及針閥運(yùn)動(dòng)對其內(nèi)部空穴分布、湍動(dòng)能分布、噴孔出口平均流速及流量系數(shù)的影響規(guī)律,并與圓柱形噴孔噴嘴進(jìn)行了對比分析。結(jié)果表明:對于漸縮形噴孔噴嘴,噴油壓力的提高或針閥開啟速度的加快,均可增強(qiáng)噴孔內(nèi)的空化效應(yīng),強(qiáng)化噴孔內(nèi)的液流紊亂,提高噴孔出口平均流速及循環(huán)噴油量,這對于燃油噴射及霧化的改善、柴油機(jī)性能的提高都是有利的;隨著噴油背壓的增加,噴嘴的流量系數(shù)雖略有提高,但噴孔內(nèi)的空化效應(yīng)、液流紊亂及噴孔出口平均流速均逐漸降低;相同噴射條件或針閥升程下,噴嘴內(nèi)的空化效應(yīng)弱于圓柱形噴孔噴嘴,噴孔出口平均流速及流量系數(shù)高于圓柱形噴孔噴嘴。

    Abstract:

    The three-dimensional numerical simulation of gas-liquid two-phase flow in diesel nozzle with convergent conical orifice(CDN)was carried out by using the mixed multiphase cavitation flow model, and the effects of injection pressure, injection back pressure and needle valve movement on the cavitating distribution, the turbulent kinetic energy distribution, the mean flow velocity at outlet(MFVO) and the discharge coefficient were analysed. The results show that the increasing in the injection pressure or the needle valve`s open velocity will enhance the cavitation effect, strengthen the flow disturbance, improve MFVO and the cycle fuel injection quantity, which are beneficial to the performance of diesel engine, the fuel injection and atomization; with the increase of the injection back pressure, the discharge coefficient of CDN is increased slightly, but the cavitation effect, the flow disturbance and MFVO are decreased gradually; under the same injection condition or needle valve lift, the cavitation effect of CDN is weaker than that of diesel nozzle with cylindrical orifice, MFVO and the discharge coefficient of CDN are higher than those of diesel nozzle with cylindrical orifice.

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崔慧峰,羅福強(qiáng),董少鋒,梁 昱,周立迎.柴油機(jī)漸縮形噴孔噴嘴流動(dòng)特性研究[J].農(nóng)業(yè)機(jī)械學(xué)報(bào),2013,44(11):19-25. Cui Huifeng, Luo Fuqiang, Dong Shaofeng, Liang Yu, Zhou Liying. Flow Characteristics in Diesel Nozzle with Convergent Conical Orifice[J]. Transactions of the Chinese Society for Agricultural Machinery,2013,44(11):19-25.

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  • 在線發(fā)布日期: 2013-11-07
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