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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 relating to Compression Pressures, Volumetric Efficiency and air flows.

Identifier  ExFiles\Box 17\6\  Scan147
Date  24th August 1933 guessed
  
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Calculations relating to Compression Pressures, Volumetric Efficiency and air flows.

(1) Calculations of Vol. Efficiency from compression pressure:-

clearance vol = 301.5 cc ( 5.5:1 C.R.)
S swept vol = 1356.0 cc

Set P = compression pressure - absolute.
V = vol compressed gas would, occupy at atmospheric pressure PA{Mr Paterson}

∴ P x (301.5)^1.4 = PA{Mr Paterson} x V^1.4

or V^1.4 = (P/PA{Mr Paterson}) x (301.5)^1.4

∴ log V = (1/1.4) log (P/PA{Mr Paterson}) + log 301.5

Hence V

Volumetric efficiency = ((V - 301.5) / 1356) x 100

E.83906 Large inlet valve head.

Speed. | Compress. Press. (lbs/sq.in. gauge) | Atmos. press. lbs.sq.in. abs. | Volumetric efficiency. | Air/min. (cu. ft/min)
3500 | 100 | 14.52 | 75.5 | 63.2
3250 | 105.5 | 14.52 | 78.8 | 61.3
3000 | 110.5 | 14.52 | 81.5 | 58.2
2750 | 114.5 | 14.52 | 83.9 | 55.2
2500 | 115.5 | 14.52 | 84.5 | 53.5
  
  


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