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).
Explanatory document for the Stancliffe Heat Interchanger for oil cooling, detailing its principles and performance.
| Identifier | ExFiles\Box 15\6\ Scan086 | |
| Date | 13th September 1929 guessed | |
| STANCLIFFE HEAT INTERCHANGER FOR OIL COOLING. WHAT IT IS. The Stancliffe Cooler is a Heat Interchanger for cooling oil and incorporates new principles and methods, having for its chief feature a mechanical aid to heat transfer-ence. WHAT IT DOES. Its cooling performance is 4 to 5 times greater than can be obtained from a plain tube cooler at any given velocity. The Cooling rate is a constant per square foot per degree of temperature difference at all temperatures and at any viscosity. Its performance is continuously maintained. HOW IT WORKS. The surface of the tube is continually wiped and the oil film continuously removed and renewed. EXISTING OIL COOLING PRINCIPLES. It is generally recognised that in the case of oil cooling by the Plain Tube Method, a considerable proportion of the resistance to heat transfer from oil to tube is due to the existence of a highly viscous film of oil which adheres to the wall of the tube. Heat flow can only take place through this film by conduction, and as the conductivity of oil is very low it is obvious that this film is the main reason for the low rates of heat transfer in the case of viscous liquids and any agitation or removal of such film will be conducive to improved results. Agitation can be produced by increasing the velocity of the oil through the tube, thereby causing a turbulent state of flow in the oil, and changing the flow of heat from conduction to convection. This necessitates such a high pressure drop through the tubes of the Cooler that it becomes impracticable to get a greatly increased rate of heat transfer by this means. STANCLIFFE OIL COOLING PRINCIPLES Successfully overcome film difficulties, a new film of hot oil being continually presented to the cooling surface. A rotor fitted with blades or wipers is revolved inside the cooling tube, thereby causing the film to be renewed and the heat flow from oil to tube to be accelerated owing to the displacement of particles of oil in the film itself, together with the induced motion of the particles in the core of the oil. This method of increasing the performance of the Cooler is obtained with a small pressure drop through the tubes. [Right Side Content] STANCLIFFE HEAT INTERCHANGER FOR OIL COOLING. DETAIL OF ROTOR. COOLING TUBE. ROTOR. SECURING STRIP. FLEXIBLE BLADE. DRIVING SPINDLE. OIL SPACE. [Graph Content] RATE OF HEAT TRANSFERENCE. B.T.U's / ☐'' / °FAH / HOUR. ROTOR REVOLVING AT 240 R.P.M. ADDITIONAL DUTY OBTAINED. ROTOR STATIONARY. OIL VELOCITY - FEET PER SECOND. DIAGRAM SHOWING ADVANTAGE OF "STANCLIFFE" PRINCIPLE OF CONTINUOUS REMOVAL OF OIL FILM. [Graph Annotations] --16 LBS. OIL/MIN. FROM 152°F to 111.6°F.{Mr Friese} --8.75 LBS. OIL/MIN. FROM 154°F to 92.2°F.{Mr Friese} --5.3 LBS. OIL/MIN. FROM 152.8°F to 77.3°F.{Mr Friese} --2.8 LBS. OIL/MIN. FROM 151°F to 51°F.{Mr Friese} --14.2 LBS. OIL/MIN. FROM 156.5°F to 139.8°F.{Mr Friese} --8.8 LBS. OIL/MIN. FROM 154.2°F to 133.8°F.{Mr Friese} --3 LBS. OIL/MIN. FROM 153°F to 127°F.{Mr Friese} | ||