Mr Meghdad Pishgooie, Seyed Masoud Hosseini Sarvari, Seyed Hossein Mansouri,
Volume 9, Issue 1 (3-2019)
Abstract
The purpose of this study is to investigate the effect of radiation heat transfer on temperature distribution and heat flux to the walls of a diesel engine. A diffusion flame is modeled in a simple cylindrical geometry and boundary conditions are defined. A specific solver which can model the turbulent diffusion flame by considering radiation in participating media is used to solve the problem. The solver is verified using experimental data of a furnace. The results show that with considering radiation and non-gray effects in the model, the flame temperature is calculated higher than that with ignoring these effects (about 11% in problem considered in this study).
Mr. Seyed Ali Mousavi, Dr. Saeed Mahjoub Moghadas, Dr. Hosein Mansouri,
Volume 16, Issue 1 (3-2026)
Abstract
In the automotive industry, reducing torsional vibrations caused by combustion irregularities and internal inertial forces is essential for improving powertrain quality, NVH (Noise, Vibration, and Harshness), and component durability. This study introduces and analyzes an innovative dual mass flywheel (DMF) with polymer bearings, aimed at enhancing torsional damping and ensuring smoother torque transmission in six-cylinder gasoline engines. The DMF consists of two masses, low-stiffness springs, and polymer bearings, all thoroughly modeled. Both linear and nonlinear dynamic analyses were performed, incorporating factors such as centrifugal force, nonlinear friction, and viscous damping. Component parameters were obtained via modal tests and experimental measurements. To validate the model, cylinder pressure and torque data were collected using sensors and a dynamometer, then compared with simulation results. Results reveal that employing the DMF reduces output torque fluctuations by up to 89.9% and significantly increases torsional vibration damping without a notable weight increase. Compared with a single-mass flywheel of equal inertia, the DMF decreased torque fluctuation amplitude by 46%, 41%, and 38% at 2250, 3000, and 3750 rpm, respectively. Achieving similar damping with a single-mass flywheel would require over an 80% mass increase. The nonlinear model provided a close match to experimental data, with simulation error below 5%. Overall, this integrated approach demonstrates that the dual mass flywheel with polymer bearings improves dynamic engine performance, NVH, and powertrain durability. These findings support the development of lighter, more advanced powertrain systems for next-generation vehicles.
