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Spray characteristics are considered as influencing factors which determine air-fuel mixing and combustion in a diesel engine combustion chamber.Almost all modern diesel engines are fitted with high pressure common rail injection system and multi-hole injectors.In the present work,spray characteristics are studied for a multihole common rail injector with all nozzle holes open and with a single nozzle hole open.This is important as in the characterization of multi-plume dense sprays like diesel,often a single-plume is used by blocking the other nozzle holes.Experiments have been conducted in a constant volume,high pressure,and high temperature chamber with various injection pressures and at various ambient conditions.A six-hole injector is considered for the study.The penetration and cone angle of the spray from each hole is measured and the hole-to-hole variation is studied.Later,five holes of the injector are blocked by micro welding and the remaining single-plume has been characterized and compared with multi-plume spray.It has been observed that hole-to-hole variation in respect with spray penetration and cone angle are minimal both at lower and higher temperatures.The study also shows that the penetration length and cone angle of the single-plume matches well with that of the multi-plumes at all pressure and temperature conditions.The spray from the single-hole has been characterized by both Mie scattering and backlit shadow imaging techniques to compare the penetration length and cone angle measured from the two imaging techniques.