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 supercharger pressure measurements and calculations for adiabatic efficiency.
| Identifier | ExFiles\Box 42\3\ Scan051 | |
| Date | 1st December 1926 guessed | |
| contd :- -6- Outlet pressure / Eye pressure = +3 / +2 and in the second case (B) Outlet pressure / Drum pressure = +3 / +1 The first set of figures give a truer value, since our pressure measurements do not take into account the kinetic energy of the air entering and leaving the blower, which in this case are approximately equal, and therefore cancel. We have not yet run the supercharger with a petrol-air mixture as we do not know the index of compression for the mixture. Comparative results can be obtained with air alone, and we are not then faced with the difficulty of disposing of large quantities of unburnt petrol vapour. (1) Adiabatic efficiency. Let T1 = absolute air temp. before compression. T2 = absolute " " after " T2¹ = estimated absolute temp. after ideal adiabatic compression. r = ratio of compression. Then T2¹ = T1 (r) ^ ((n-1)/n) Adiabatic efficiency = (T2¹ - T1) / (T2 - T1) = (T1 (r^((n-1)/n) - 1)) / (T2 - T1) For air n = 1.41 contd :- | ||