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).
Test results from plugging suction chamber holes to reduce pressure wave effects and a list of further investigations.
| Identifier | ExFiles\Box 179b\3\ img095 | |
| Date | 1st February 1933 | |
| -5- rather large spill since a pressure would be generated in the suction chamber and cause leakage to the spill chamber. This was merely a working theory put forward to explain the rather curious facts; the accuracy of it has still to be proved. To reduce this wave effect it was decided to plug some of the suction chamber holes. It was thought that the effect of this might be to retard the rate of filling the pump chamber and thus reduce the wave effect. This proved to be the case as the tests to be described show. The above experiments and considerations lead to a series of tests (details of which are shown in Table 1) in which the delivery, pump lag and injection period curves were obtained for a pump speed range of 336 R.P.M. to 1000 R.P.M. various suction chamber holes being plugged. The positions of the suction chamber holes referred to as Nos. 1, 2 etc. are shown in Fig.1. TABLE 1. Affect of plugging suction chamber holes. Position of 1000 R.P.M. (pump) Hole. Max. Injection. Normal Injection. For position Discharge Pump Injection see Fig.1. ccs/cycle Lag Period (º) (º) All 6 holes open .441 -14.0 41.5 No. 1 .430 2.5 23.0 No. 2 .448 2.75 23.0 No. 3 .441 3.0 24.7 No. 4 .441 3.0 24.5 Nos. 2 & 5 .444 1.0 25.5 In addition to the above tests the following subsidiary investigations were carried out :- (1) Affect of fitting air vessel on suction pipe Figs. 5, 6 & 7 Hole No.1. (2) Affect of removing delivery valve Figs. 10,11 & 12 Hole No.3 (3) Comparison of injection period and pump lag at maximum and normal injection. Fig.7 Hole No.3 (4) Delivery and spill curves at normal and maximum injection. Fig.8. Hole No.3 | ||