TY - JOUR
T1 - A New Cavitation Algorithm to Support the Interpretation of LIF Measurements of Piston Rings
AU - Ruch, Fabian H.
AU - Wachtmeister, Georg
N1 - Publisher Copyright:
© 2020 SAE International. All Rights Reserved.
PY - 2020/4/14
Y1 - 2020/4/14
N2 - Laser induced fluorescence (LIF) is used to investigate oil transport mechanisms under real engine conditions. The engine oil is mixed with a dye that can be induced by a laser. The emitted light intensity from the dye correlates with the residual oil at the sensor position and the resulting oil film thicknesses can be precisely determined for each crank angle. However, the general expectation is not always achieved, e.g. an exact representation of piston ring barrel shapes. In order to investigate the responsible lubrication effects of this behavior, a new cavitation algorithm for the Reynolds equation has been developed. The solution retains the mass conservation and does not use any switch function in its mathematical approach. In contrast to common approaches, no vapor-liquid ratio is used, but one or several bigger bubbles are approximated, as have been observed in other experiments already. As a result, not only the known boundary conditions for the Reynolds equation become unnecessary, but the solution also gives a clearer idea as to the shape of the cavitation bubble. The combination of simulated oil film thicknesses, the resulting cavitation bubbles and the fixed field of view from the LIF sensor allows a reproduction of the measurement signal. The comparison of measurement and simulation exhibits a high correlation, and thus enables a deeper knowledge and understanding of the real conditions inside a combustion engine. On the other hand, it can be seen that effects such as a decrease in the LIF signal in the cavitation area is much lower than would be expected according to the literature.
AB - Laser induced fluorescence (LIF) is used to investigate oil transport mechanisms under real engine conditions. The engine oil is mixed with a dye that can be induced by a laser. The emitted light intensity from the dye correlates with the residual oil at the sensor position and the resulting oil film thicknesses can be precisely determined for each crank angle. However, the general expectation is not always achieved, e.g. an exact representation of piston ring barrel shapes. In order to investigate the responsible lubrication effects of this behavior, a new cavitation algorithm for the Reynolds equation has been developed. The solution retains the mass conservation and does not use any switch function in its mathematical approach. In contrast to common approaches, no vapor-liquid ratio is used, but one or several bigger bubbles are approximated, as have been observed in other experiments already. As a result, not only the known boundary conditions for the Reynolds equation become unnecessary, but the solution also gives a clearer idea as to the shape of the cavitation bubble. The combination of simulated oil film thicknesses, the resulting cavitation bubbles and the fixed field of view from the LIF sensor allows a reproduction of the measurement signal. The comparison of measurement and simulation exhibits a high correlation, and thus enables a deeper knowledge and understanding of the real conditions inside a combustion engine. On the other hand, it can be seen that effects such as a decrease in the LIF signal in the cavitation area is much lower than would be expected according to the literature.
UR - http://www.scopus.com/inward/record.url?scp=85083834731&partnerID=8YFLogxK
U2 - 10.4271/2020-01-1091
DO - 10.4271/2020-01-1091
M3 - Conference article
AN - SCOPUS:85083834731
SN - 0148-7191
VL - 2020-April
JO - SAE Technical Papers
JF - SAE Technical Papers
IS - April
T2 - SAE 2020 World Congress Experience, WCX 2020
Y2 - 21 April 2020 through 23 April 2020
ER -