Thrust of Poppet Valve

Abstract

Analysis and experiments were performed to study the static characteristics of the thrust of poppet valves. Valves with cone angles between 40 degrees and 90 degrees were tested under different conditions. Experimental result reveals the momentum theory is valid for the estimation of the thrust. For poppet valves having lappings with valve seats, pressure integrals on the seats are required for the estimation of the thrusts. The boundary layer theory was applied to the flow in the clearances between valves and valve-seats, thence pressure integrals were calculated. Developed formulae were different whether the flow was laminar or turbulent. Thrust coefficient in the transition region lay between two calculated values, hence only rough estimation was thought possible. In the regions considered laminar or turbulent, analytical results coincided fairly well with experimental results.