Journal of the Society of Motion Picture and Television Engineers (1950-1954)

RESEARCH APPLICATIONS The new Isotran camera has been sed at rates up to 50,000 frames/sec in study of scavenging, turbulence, fuel njection, combustion, and exhaust blowlown in a cylinder of a GMV engine nanufactured by The Cooper-Bessemer Corporation. This sparkignited engine s of the two-stroke-cycle type, and uses atural gas as a fuel. The bore and troke are each 14 in. The engine, nost often built in 10-cylinder V arangement of approximately 1100 hp, s in widespread use for the pumping of atural gas through distribution pipeines. All of the processes enumerated lave been made visible by the schlieren nethod in the high-speed photographs, lie photographs have given CooperJessemer valuable information conerning these phenomena, and have in •eneral verified conclusions previously cached on other bases and used as esign data. The high-speed photoraphs taken in this study over a period f two years are the first known of jhenomena occurring within engine ylinders of comparable size. Figure 9 is a reproduction of a highpeed motion picture of combustion in ie GMV engine, exposed by the chlieren method at 20,000 frames/sec, 'hese photographs are reproduced here, n preference to those taken at 50,000 rames/sec, because the speed of the ihenomena observed does not justify le higher repetition rate. For the photographs of Fig. 9, the )osition of the igniting spark was placed vithin the field of view, so that ignition ag could be determined. The position f the igniting spark, at the apparent ntersection of the wire electrodes, is esignated by the letter S in frame A-3. The order of exposure of the frames of ig. 9 is from left to right through low A, then from left to right through low B, and so on. The three round lack spots appearing in most frames are ic heads of three cap screws holding a mirror to the top of the piston. The diameter of this mirror, located near the edge of the 14-in. piston, is 2£ in. A glass window of the same diameter, mounted in the cylinder head, permits the schlieren view into the combustion chamber. Flame first becomes visible as a small dark cloud in the vicinity of the igniting spark at about frame G-4. Throughout the remaining frames of Row C, all frames of Rows D to G, and the first five or six frames of Row H, the flame travels across the entire visible part of the combustion chamber. During the remaining frames of Row H and the early frames of Row I the flame burns itself out in all visible parts of the chamber. The mottled appearance of the frames in Rows A and B, and in Rows J and K, is due to stratification of scavenging air, residual gas from the previous combustion cycle, and injected gaseous fuel. In the projected motion pictures, movements of these stratifications are plainly visible. Besides its use in the study of phenomena in the cylinder of the CooperBessemer GMV engine, the new Isotran camera is being used in a study of the fundamental physical nature of knock in a spark-ignited piston engine burning various types of liquid hydrocarbon. This project is sponsored cooperatively through the Coordinating Research Council, Inc., with financial support by the automotive, aircraft and oil industries, and by the Bureau of Aeronautics, Department of the Navy. Photographs taken on this project are not yet available for publication. The new Isotran camera is available for additional research projects, which might be sponsored by industry or Government, several of which may run concurrently. Most combustion phenomena, exclusive of explosions, fall within a speed range for which this camera is best suited. Most large-scale move Miller and Scharf: Isotransport Camera 143