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).
Calculations and proposals for a cooling fan and tube block design.
| Identifier | ExFiles\Box 25\1\ Scan005 | |
| Date | 31th October 1929 | |
| LrL/AD31.10.29. contd. -3- In this type of tube block, there is 1 m.m. gap between the tubes which gives 900 tubes per sq. ft. frontal area. The air way through the tubes is 75% of the total frontal area. volume of cooling air induced through the tubes = Vo = 1.25 x .75 x 7000 = 6560 cu.ft/min. weight of cooling air per min. = 6560 x .075 = 492 lbs. Cooling Fan. I suggest we have an aerofoil bladed fan rotating in a duct with a relatively small running clearance at the tips. The air will be drawn through the tubes, the areas of passages to and from the fan conveying and diverging respectively. The principle involved, aims at maintaining a uniform velocity of air through the tubes and at the inlet, and a change from kenetic to pressure in the diverging outlet. This difference in pressure being the head required to overcome the drag losses through the condenser etc. By this method we may anticipate fan efficiency of 75%. Horse Power to drive Fan. The drag losses of this type of tube block, as measured in the wind channel is approx. 10 lbs per sq. ft. | ||