Unravelling tumble and swirl in a unique water-analogue engine model

Abstract

The in-cylinder flow prior to combustion is considered to be one of the most important aspects controlling the combustion process in an engine. More specifically, the large-scale structures present in the cylinder, so-called tumble and swirl, before compression are believed to play a major role into the mixing and combustion processes. Their development during the intake stroke and their final strength depend mainly (but not only) on the inlet port design. In the present study, the turbulent large-scale structures during the intake stroke are investigated in a unique water-analogue engine where inlet ports and valve timings can easily be configured and tested. The flow field in the cylinder volume is reconstructed through multi-planar stereoscopic particle image velocimetry measurements which reveal a wealth of vortical structures during the stroke’s various phases. The aim of the present paper is to present and show results from a unique setup which can serve as a test bench for optimisation of inlet port designs to obtain a desired vortical pattern in the cylinder after the intake stroke is finished. This setup can simulate the intake stroke in a much more realistic way as compared to a through-flow setup with a fixed valve lift.Graphical Abstract Electronic supplementary materialThe online version of this article (10.1007/s12650-018-0485-3) contains supplementary material, which is available to authorized users.

Investigation of Flow Fields Emanating from Two Parallel Inlet Valves Using LES, PIV, and POD

“…Experimental studies on in-cylinder flow in combustion engines often focus on one or two specific planes, such as the symmetry plane, tumble plane, parallel planes, cross-tumble plane (orthogonal to the symmetry plane), or horizontal planes [7,54,[58][59][60][61]. While there are various optically accessible engine test rigs that enable the application of different optical techniques, occasionally, there is a need for ad-hoc test rigs to replicate specific air flows or to provide better accessibility [19,[33][34][35]40,[62][63][64][65][66][67]. However, a drawback of such engine test benches is frequently lower flexibility regarding the operating parameters, such as the intake pressure and temperature, as well as the limitation to stationary flows with constant valve lifts.…”

Investigation of Air Movement in Cylinder in Diesel Internal Combustion Engines and Comparison of Measurement Methods

“…Silindirde istenen girdap modelini elde etmek amacıyla, tasarım optimizasyonu için test düzenekleri kullanılmaktadır. Bu sayede giriş stroku, sabit bir supap kaldırma ile baştan sona akış kurulumuna kıyasla çok daha gerçekçi bir şekilde simüle edilebilmektedir [3]. Girdap hareketini etkileyen önemli parametrelerden biri motordaki hava emiş kanalının tasarımıdır.…”