Effects of friction disc surface groove on speed-regulating start

Purpose - The purpose of this paper is to reveal the mechanism of effect of surface groove on speed-regulating start.Design methodology approach - This paper investigates numerically and analytically the torque transfer and load capacity of oil film between separator and friction disc with grooves commonly used at present by solving simultaneous equations: modified Reynolds, energy, and temperature-viscosity equations.Findings - The results show friction discs with wider and deeper groove are not suitable for speed-regulating start. To improve performance of speed-regulating start, distribution and size of surface groove should be designed to obtain ascending trend of oil film load capacity during startup process.Originality value - This paper reveals the mechanism of effect of surface groove on speed-regulating start and facilitates the conceptual design of speed-regulating start control system.