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).
Radiator cooling efficiency and heat dissipation, applying Newton's Law of Cooling.
| Identifier | ExFiles\Box 24\4\ Scan297 | |
| Date | 25th November 1924 | |
| R.R. 403A (SOH) (D.A. 652 20-2-24) J.H.D. -2- EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG25.11.24. circulation in this way being maintained normally by the pump. Top and bottom water temperatures and atmospheric readings were taken at fixed intervals throughout the run until the mean radiator temperature fell to 40°C. Both way readings were taken in each case and the tests carried out on a straight stretch of road to eliminate the effect of wind. It was found on investigation that these curves approx- imately follow Newtons Laws of Cooling. The capacity for heat dissipation of the RR. radiator is therefore proportional to the difference in temperature between the mean radiator temperature and the atmosphere. From the various cooling curves, the efficiency of the system under different conditions was deter- mined, the units used being B.Th.U's dissipated/min. per F° difference in temperature between mean matrix temperature and atmosphere. METHOD 'B'. Having established that the cooling of the radiator follows Newtons Law, it follows that δt, the difference in temperature between the mean radiator temperature and atmosphere required to dissipate a fixed quantity of heat units per min. will indicate directly the efficiency of the system. That is, if one radiator will dissipate the heat generated on full throttle at 30 m.p.h. when δt = 70°C, and another necessitates δt being 80°C, to get rid of the same quantity of heat, then the first radiator shews a gain of efficiency of 12½% over the second. contd :- | ||