Detailed study of steady incylinder flow and turbulence using stereo-PIV
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Detaljerad studie av flöde och turbulens med stereo-PIV i stabil innercylinder. (Swedish)
Due to the increase of global warming effects and new legislation in terms of consumption and emissions of engines, it is today of paramount importance to know exactly the flow behavior inside cylinders of engines to be able to improve the combustion process. Until now, at Scania, cylinder heads have been tested in terms of flow coefficient measurements and torque measurements using steady flowrigs. In this project, however, the non-intrusive and optical technique called stereoscopic PIV has been used in ort of this project has been to study and put into place the PIV setup in order to get the best results from the measurements. Using the stereo technique, the three components of the steady instantaneous velocity in a plane perpendicular to the cylinder axis have been determined. The cylinder and cylinder head were mounted over a device pumping air through the inlet valves reproducing the intake stroke of the engine but with a steady flow. This is useful in order to do different measurements testing several valve lifts and pressure drop in a controlled way. A steady flow is assumed stating that the motion of the valves is slow in comparison to the timescales of the flow. The study of the ensemble averaged flow fields and the turbulence through an analysis of the anisotropic tensor showed an important dependence on the valve lift whereas small dependence is on the pressure drop applied could be noticed indicating that the in-cylinder motion is the same for all engine speeds. The results were then compared to LES simulations and honeycomb measurements and they were in a good agreement.
Place, publisher, year, edition, pages
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-92165OAI: oai:DiVA.org:kth-92165DiVA: diva2:512553
Alfredsson, Henrik, Professor