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).
Mathematical formulas for calculating temperature and density ratios at altitude.
| Identifier | ExFiles\Box 149a\2\ scan0330 | |
| Date | 13th January 1936 | |
| -3- Hs{Lord Ernest Hives - Chair}/Std.1/JH.13.1.36. Let B = temp. for boiling to take place at altitude. " r = ratio of density at altitude / density at ground level. Assuming that system is vented to atmosphere without any pressure valve. ∴ TG = 100 - ΔG (sea level, H being dissipation) and TA = B - ΔA at altitude, heat to be dissapted = H(.167 + .834k) from a ∴ ΔA = ΔG (.167 + .834k) / r .83 = (100 - TG) (.167 + .834k) / r .83 ∴ TA = B - (100-TG) (.167 + .834k) / r .83 -----(b) Let TC = altitude corrected critical AIR temp. :- °C tA = air temp. at altitude. :- °C tG = " " " sea level. :- °C From curves on sheet(1) We have the following relationships:- (1) tA = tG - h/500 = tG - .002h. (2) B = 100 - .001h. (3) k = 1 - .00003h. (4) r = 1 - .000025h. } h = altitude in ft TC = TA + tG = TA + .002h (from(1)) | ||