圧縮機の吐出用リード弁における開き遅れ挙動の計算（弁変形-ガス流れ-油膜流れ連成計算のためのモデル化）

概要

論文の詳細を見る
The opening delay of a discharge reed valve for compressors caused by the oil film in the clearance between the reed and the valve seat is investigated. The coupling calculation model which consists of the reed deformation, the gas flow and the oil film flow is developed. The two-dimensional reed deformation is expressed by expanding natural modes that are obtained by the finite element method using shell elements. The gas flow is expressed by the thermodynamic model under the assumption of the internal reversible process. The two-dimensional oil film pressure is obtained by solving numerically the Reynolds' equation through the finite volume method. In addition to the case in which cavitation in the oil film is not taken into account, two cavitation models are tested; the static cavitation model (Reynolds' condition) in which the minimum oil pressure is set to absolute zero and the dynamic cavitation model in which the bubble expansion is directly simulated. Comparisons between calculation results and the experimental result show that the dynamic cavitation model in which the oil film pressure can fall to the absolute negative (tensile in the liquid) is required to reproduce accurately the opening delay time in the experiment.