Review of theory of distortion and disintegration of liquid streams

A review of prechamber ignition systems as lean combustion technology for SI engines

A collection of techniques is presented for the visualization of separated turbulent flows at high speeds. Some of these techniques—including a method of generating a localized vapor visualization—have not been available previously. Others, such as the conical shadowgraph and stereoscopic schlieren methods, have been used before in other contexts. Here, all the available techniques are applied to the study of three-dimensi onal supersonic flows generated by swept compression corners. The paper discusses the techniques and some of the fluid mechanical insights revealed by the visualizations, including the structure of the observed three-dimensional flow separations and associated shock wave systems.

Flow visualization methods for separated three-dimensional shock wave/turbulent boundary-layer interactions

Revue de differentes methodes de visualisation: techniques de traceurs, thermographie infrarouge, interferometrie laser et holographie, tomographie, photographie a grande vitesse videographie a grande vitesse, traitements optique et digital des images. Application en aerodynamique

Modern Developments in Flow Visualization

A novel optical instrumentation system has been developed for on-line continuous measurement of two-dimensional temperature distribution of a combustion flame. The system comprises a special optical assembly, a charged coupled device camera, a frame-grabber and associated software. Based on the two-colour principle, the transient two-dimensional temperature of a flame is determined from the ratio of grey levels of corresponding pixels within two images, which are simultaneously captured at two different wavelengths. Accordingly, the instantaneous two-dimensional temperature distribution of the flame is presented by pseudo-colour. Discreet considerations in the design of the instrumentation system are also described, including the choice of wavelengths, correction of location and intensity of pixels, elimination of noise, and calibration of the instrument factor. A series of experiments was conducted for butane-fired open flames on a combustion test rig. The results show that the temperature of a fuel-rich...

Transient two-dimensional temperature measurement of open flames by dual-spectral image analysis

To examine the effect of torch jet direction on the combustion characteristics and engine performances, a spark-ignition engine with each divided chamber having a torch nozzle of different flow direction is used by changing the torch nozzle area, prechamber volume and air-fuel ratio, while keeping the engine speed of 1000 rpm. Typical pressure diagrams for different torch jet directions are analyzed to obtain such combustion characteristics as the crank angles of combustion start and finish, heat release rate and mass burned fraction. The engine performances, e.g. mean effective pressure and specific fuel consumption, are also measured. As a result, it can be made clear not only the effect of torch jet direction on the combustion characteristics, but also the relationship between the combustion characteristics and the engine performances for different torch jet directions.

Effect of Torch Jet Direction on Combustion and Performance of a Prechamber Spark-Ignition Engine

To make clear the influence of a torch jet flow on the combustion process, a laser Doppler anemometer (LDA) is used to measure the mean velocity and turbulence intensity in a spark ignition engine with an unscavenged prechamber connected to a main chamber by a torch nozzle of different area sizes. The test engine is operated at a constant speed of 16.7 rps (1000 rpm), a constant volumetric efficiency of 80 +- 2% and MBT for each torch nozzle ara under firing as well as motored conditions. The LDA system is a dual beam forward scatter type, and its signals are acquired quickly and stored in a memory through a frequency tracking system.

LDA Measurement of Turbulent Flow in a Motored and Firing Spark-Ignition Engine with a Horizontal Prechamber

Temperature Measurements of Combustion Gas in a Spark Ignition Engine by Infrared Monochromatic Pyometry

Up to date, a pressure indicator diagram has been usually used to estimate the heat release rate and mass burned fraction and thereby analyse the combustion process in a spark ignition engine. However, this analysis has only provided unitary information on the combustion process in the engine. Recently, gas temperature diagrams measured by an infrared absorptionemission pyrometer were recognized to give information on the combustion process at various stations in the combustion chamber. The temperature measuring technique and its results are already described in a previous paper. In this paper, to make a more reasonable model of torch combustion in a spark ignition engine with an auxiliary chamber, gas temperature diagrams measured under a wide range of air-fuel ratio and torch nozzle diameter are analysed to determine such combustion characteristics show a reasonable agreement with those estimated from the pressure diagrams. Accordingly, the combustion analysis with gas temperature diagrams are found to provide such a lot of useful local information for combustion modeling as optimum diameter of torch nozzle, two-step combustion and reverse flow through torch nozzle.

Tsuyoshi Asanuma

Papers

Effect of Torch Jet Direction on Combustion and Performance of a Prechamber Spark-Ignition Engine

LDA Measurement of Turbulent Flow in a Motored and Firing Spark-Ignition Engine with a Horizontal Prechamber

Temperature Measurements of Combustion Gas in a Spark Ignition Engine by Infrared Monochromatic Pyometry

Combustion analysis with gas temperature diagrams measured in a prechamber spark ignition engine

Combustion gas temperature in a prechamber spark ignition engine measured by infrared pyrometer