Figure 9 ISFC comparison for various initial charge temperatures.
Related Figures (19)
Figure 1. 3D moving mesh at 40° CA BTDC. Table. Engine specifications. engine and contained a maximum of 73,246 cells at a 130° CA BTDC. Different grid densities were tested prior to the study, and the present resolution was found to give adequately grid-independent results with a reasonable CPU run time. The AVL FIRE code solves the compressible, turbulent, 3-dimensional transient conservation equations for reacting multicomponent gas mixtures. The turbulent flow within the combustior chamber is simulated using the RNG k — « turbulence model, modified for variable-density engine flows (Har and Reitz, 1995), considered to be one of the suitable turbulence models for engine simulation studies. Initia conditions for turbulence kinetic energy (TKE) and turbulence length scale (TLS) were calculated according tc the formulation provided in the AVL FIRE User Manual (2006) and described below: Figure 2a. Model validation under injection timing of 130° CA BTDC, spark timing of 11° CA BTDC. Figure 2a. Model validation under injection timing of Figure2c. Model validation under injection timing of 80° CA BTDC, spark timing of 8° CA BTD¢ Figure 2b. Model validation under injection timing of 100° CA BTDC, spark timing of 11° CA BTDC. Figure 3. Comparison between calculated and measured NO; emission under injection timing of 130° CA BTDC, spark timing of 11° CA BTDC. Figure 4b. Effect of initial charge temperature on cylin- der temperature under injection timing of 80° CA BTDC. Figure 4a. Effect of initial charge temperature on cylin- der pressure under injection timing of 80° CA BTDC. Figure 4a. Effect of initial charge temperature on cylin- Figure 4b. Effect of initial charge temperature on cylin- Figure 5a. Effect of initial charge temperature on cylin- der pressure under injection timing of 100° CA BTDC. Figure 5a. Effect of initial charge temperature on cylin- der pressure under injection timing of 100° CA BTDC. Figure 6a. Effect of initial charge temperature on cylin- der pressure under injection timing of 130° CA BTDC. Figure 6a. Effect of initial charge temperature on cylin- Figure 6b. Effect of initial charge temperature on cylinder temperature under injection timing of 130° CA BTDC. Figure 5b. Effect of initial charge temperature on cylinder temperature under injection timing of 100° CA BTDC. Figure 8. IMEP comparison for various initial charge temperatures. 4.2. Effect of initial charge pressure Figure 7. NO, comparison for various initial charge temperatures. Figure 11b. Effect of initial charge pressure on cylinder temperature under injection timing of 100° CA BTDC. Figure 1la. Effect of initial charge pressure on cylinde1 pressure under injection timing of 100° CA BTDC. Figure 11b. Effect of initial charge pressure on cylinder Figure 1la. Effect of initial charge pressure on cylinder pressure under injection timing of 100° CA BTDC. Figure 10b. Effect of initial charge pressure on cylinder temperature under injection timing of 80° CA BTDC. Figure 10a. Effect of initial charge pressure on cylinde pressure under injection timing of 80° CA BTDC. Figure 10a. Effect of initial charge pressure on cylinder Figure 10b. Effect of initial charge pressure on cylinder Figures 10a, 10b, lla, 11b, 12a, and 12b indicate the in-cylinder pressure and temperature at various initial charge pressures. As can be seen, by increasing the initial pressure, the mean and maximum in-cylinde1 pressure is increased. Figures 10b, 11b, and 12b show that in-cylinder temperature is inversely proportional to the initial charge pressure. This is due to the fact that with the increasing of the initial pressure, the inlet ait mass increases; however, the injected hydrogen mass is fixed. This implies that the fuel-air mixture becomes leaner than that at the naturally aspirated condition. Since nonluminous burning will occur in the lean mixture condition, this can explain why the in-cylinder temperature decreases with the increasing of the initial pressure. temperature under injection timing of 80° CA BTDC. Figure 13. NO, comparison for various initial charge pressures. et al., 2007). Figure 12b. Effect of initial charge pressure on cylinder temperature under injection timing of 130° CA BTDC. Figure 12a. Effect of initial charge pressure on cylinde1 pressure under injection timing of 130° CA BTDC. Figure 12b. Effect of initial charge pressure on cylinder Figure 12a. Effect of initial charge pressure on cylinder Figure 14. IMEP comparison for various initial charge pressures. Figure 15. ISFC comparison for various initial charge pressures.
