The regulation mechanism of ultrasound on iso-octane combustion was analyzed from the macro and mi-cro levels.The three-dimensional computational fluid dynamics model of the original engine was calibrated using the bench test data.Based on the method of physically embedding the dynamic grid sound source surface in the combustion chamber,the ultrasonic with 20 kHz frequency and 300 μm amplitude was successfully fed into the combustion chamber.Taking the difference between the cylinder pressure with and without ultrasonic wave feeding into the combustion chamber as the ultrasonic radiation pressure disturbance,the effects of ultrasonic field excita-tion on the ignition delay period,intermediate reaction components and sensitivity analysis of iso-octane were stud-ied.By comparing and analyzing the simulation results of three ultrasonic-fed schemes S1—S3 with no ultrasonic-fed scheme S0,the results show that the S1—S3 schemes can advance the combustion phase,and the peak mole frac-tions of C3H6,IC4H8 and C2H4 in S2 and S3 are increased by 42.1％,24.7％,27.5％and 21.5％,9.6％,5.3％,respectively and the iso-octane burnout time of both schemes are advanced by 0.18 s.When the equivalence ratio is 1 and the initial temperature is 1 300 K and 1 700 K,the ignition delay period is shortened by 31.8％and 6.4％,respectively and both promote to produce a large number of OH radicals.
关键词
异辛烷/燃烧特性/燃烧调控/超声场激励/着火延迟期
Key words
iso-octane/combustion characteristics/combustion regulation/ultrasonic field excitation/ignition delay period
维普
万方数据