Analysis for internal unsteady flow of 90 degree bend nozzle with circular cross-section using mode decomposition method

Abstract

Typical thermal efficiency improvement methods for automotive engines tend to result in higher combustion temperatures. Therefore, it is important to elucidate the characteristics of oil jet behavior in order to develop highly efficient piston cooling technology. The author's research group has reported the effect of unsteadiness of the flow in the nozzle on the jet interface. In this paper, time history PIV results of flow in an acrylic nozzle with a 90° bend are analyzed using Proper Orthogonal Decomposition (POD) and dynamic mode decomposition (DMD), and the characteristic modes obtained by each method are compared and their relationship to the wave behavior of the oil jet is discussed.