A Numerical Investigation of the Effects of Piston Bowl Geometry and Spray Angle on Combustion, Performance and Emission of a Diesel Engine
Md. Nazmul Haque, Abdullah Al Rifat, Tafsirul Hassan, Md. Ifthaker Alam, Mohammad Mehedi Hasan Kazol, Md. Ashraful Islam, Abidur Rahman Adib, Mizanur RahmanABSTRACT
A piston bowl's design and spray angle improve air–fuel mixing, resulting in more complete combustion and higher efficiency. Ansys Forte 2023 R1 a CFD software was used to analyze the effects of five combustion chamber geometries of cylinder, modified re‐entrant, re‐entrant, double‐stepped, and stepped on engine performance, combustion, and emission characteristics at spray angles of 1000°, 1050°, 1100°, 1150°, and 1200°, respectively. This study looks into the effects of piston bowl shape and spray angle on engine performance and emission characteristics. The numerical investigation is carried out with a load of 0.44 MPa and a start of injection at 7° bTDC. The double stepped piston bowl with spray angles of 110°–115° has the maximum thermal efficiency and the lowest ISFC, while reducing VOC, UHC, soot, and CO emissions. The combustion and performance parameters for piston bowl geometries are optimized at spray angles of 110° and 115°. At these spray angles, improved fuel–air interaction leads to higher peak cylinder pressure, peak cylinder temperature, thermal efficiency, and ISFC consumption while producing reduced emissions. The results show that spray angle optimization is crucial, with 110°–115° emerging as the optimal spray angle range for piston bowl selection and combustion optimization. Among the bowl geometries, the double stepped demonstrate the most balanced performance‐emission trade‐off at spray angles of 110° and 115° compared to stepped, modified re‐entrant, re‐entrant, and cylindrical shapes.