From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Analysis of flame velocity and pressure rise in relation to ignition position for smooth combustion.
| Identifier | ExFiles\Box 133\1\ scan0259 | |
| Date | 21th July 1937 | |
| -6- 21.7.37. (9) (10) Clearly, as seen from Fig. 12, the unit with ignition at the apex will be rough, since maximum flame velocity occurs so late in the burning. The ignition at the base, on the other hand, will give smooth running. Referring to Fig. 4, we see now that since flame velocity is a maximum when half the volume has been burned, then, at this point, slightly less than a quarter of the pressure has been developed. This means, therefore, that the remaining three quarters of the pressure rise must be developed after the maximum flame velocity has occurred. If, therefore, we bring this point early on in the burning, such as with the ignition at the base, then as we now have a fairly long interval of time in which to burn the remaining three-quarters of the charge, smooth combustion will result; this explains why most designers endeavour to get the flame off to a good start. | ||