Structure of Swirl Chamber of Turbulent Combustion Diesel Engine

Abstract

Numerical simulation was conducted on three types of swirl chamber of turbulent combustion diesel engine, i.e. cone-shaped flat-bottomed, cylindrical flat-bottomed and spherical shape. The characteristics of flow field in cylinder were studied within the time range for the piston to move from BTDC 108°CA to BTDC 8°CA (at the instant of fuel injection), thus analyzed the changes of flow field in swirl chambers of such three different structures prior to fuel injection based on the velocity vector diagram at all times and the final temperature characteristic diagram of the flow field. The results show that: in the process of piston motion, an organized fierce vortex can be developed inside the swirl chamber, while in the vicinity of fuel nozzle, the air flow rate is 111.14m/s, 83.01m/s or 175.76m/s and the air temperature is 1384.15K, 1337.38K or 1350.46K respectively. A small fluid stagnation zone will be formed in the lower right end of the cone-shaped flat-bottomed swirl chamber or the cylindrical flat-bottomed swirl chamber and is adverse to the mixing of fuel and air. In comparison with the swirl chambers of other two structures, the smaller temperature gradient of fluid and the larger high-temperature area in the cylindrical swirl chamber are beneficial to the mixing of injected fuel and air.

Analysis on working performance of the swirl chamber diesel engine with a dual channel and an expansion angle

“…Therefore, an innovative dual channel geometry of insert with expansion angle is put forward based on the previous design principle of single channel insert . By the expansion angle of the dual channel altered, respectively, and with the gas flow interaction of the dual channel to improve the efficiency of the gas distribution and air‐fuel mixing, the regular influence of the dual channel geometry on the swirl characteristics of the swirl chamber will be studied.…”