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 radiator and pump performance, focusing on cavitation and water flow dynamics.
| Identifier | WestWitteringFiles\U\January1930-April1930\ Scan026 | |
| Date | 10th January 1930 | |
| -2- appertained at the point before cavitation started. In agreement with this, the depression on the suction side of the pump also remains constant. The cycle appears to be that the pump reaches a depression which will draw a fixed quantity of water through the radiator. The water reaches the temperature where it boils at this depression and consequently steam is formed. Instantaneously the flow ceases and the depression in consequence drops, allowing flow to recommence and completing the cycle. It is therefore clear that for any radiator with a given hydraulic restriction, there is a maximum quantity of water that can be drawn through the radiator at any temperature, and further efforts to increase this flow of water will not be successful, but on the other hand will not do any harm. In other words, the size of water pump has no influence on the maximum flow that can be obtained before cavitation takes place, it only dictates at what engine speed this maximum flow will be reached. It is therefore clear that the predominating factor in maintaining a good circulation is the hydraulic restriction of the matrix and that reducing the delivery of the pump does not help matters. Our next object was to find what possibility there was of the maximum circulation point being reached with our present standard S.S. large gap radiator. In considering this it must be born in mind that the drop across the radiator is about 10°C. and that therefore the highest temperature likely to be reached on the suction side of the pump is 85°C. At | ||