發(fā)布時(shí)間：2018-09-19 13:50

【摘要】：單缸低速試驗(yàn)表明,自由活塞內(nèi)燃發(fā)電機(jī)低速模式缸內(nèi)燃燒并不穩(wěn)定,呈間隔循環(huán)著火。為探索其原因,構(gòu)建了系統(tǒng)CFD(計(jì)算流體力學(xué))模型,對(duì)比分析了自由活塞內(nèi)燃發(fā)電機(jī)換氣過程與傳統(tǒng)二沖程內(nèi)燃機(jī)換氣過程之間的差異,通過計(jì)算解釋了試驗(yàn)中著火不穩(wěn)定的現(xiàn)象,并得到了換氣過程中影響換氣效果的關(guān)鍵因素是掃氣箱容積變化率的結(jié)論。隨后探尋改善自由活塞內(nèi)燃發(fā)電機(jī)低速不穩(wěn)定性的設(shè)計(jì)策略,在計(jì)算模型中進(jìn)一步研究了動(dòng)子(磁棒)直徑、掃氣箱容積、進(jìn)氣增壓壓力對(duì)換氣過程的影響。研究發(fā)現(xiàn):減小動(dòng)子直徑與缸徑比、對(duì)進(jìn)氣增壓能顯著改善自由活塞內(nèi)燃發(fā)電機(jī)的換氣效果,而在保證提供充分混合氣量基礎(chǔ)上掃氣箱容積的改變對(duì)換氣效果影響不大。
[Abstract]:The single cylinder low speed test shows that the combustion in the low speed mode of the free piston internal combustion generator is unstable and the combustion is intermittent cyclic ignition. In order to explore the causes, a CFD (Computational fluid Dynamics) model is constructed, and the differences between the air exchange process of the free piston internal combustion generator and the traditional two-stroke internal combustion engine are compared and analyzed. The phenomenon of unstable ignition in the test is explained by calculation, and the conclusion is drawn that the key factor affecting the ventilation effect is the volume change rate of the scavenging box. Then the design strategy to improve the low speed instability of the free piston internal combustion generator is explored. In the calculation model, the effects of the diameter of the rotor (magnetic rod), the volume of the scavenging box and the inlet pressure on the air exchange process are further studied. It is found that reducing the ratio of the diameter of the mover to the diameter of the cylinder can significantly improve the air exchange efficiency of the free piston internal combustion generator, but the change of the volume of the scavenging box has little effect on the ventilation effect on the basis of ensuring the sufficient mixture volume.
【作者單位】： 北京理工大學(xué)機(jī)械與車輛學(xué)院;
【基金】：國家自然科學(xué)基金(51276019)
【分類號(hào)】：TM314;TK441
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本文編號(hào)：2250311