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The accuracy and robustness of spray models and their implementation in current commercial CFD codes vary substantially. However, common features are that the resulting spray penetration and levels of spray-generated turbulence - two factors that strongly influence the rate of heat released during combustion - are to a great extent grid size-dependent. In the work presented here a new kind of spray model has been implemented and thoroughly tested, under various ambient conditions, in the open source code OpenFOAM. In addition, since the turbulence model applied in simulations is known to strongly affect spray penetration rates, results obtained using both the standard k-ε and RNG k-ε models have been compared. In the new spray model, designated VSB2, the traditional Lagrangian parcel has been replaced by a so-called stochastic blob containing droplets with a distribution of sizes, rather than a number of uniform-sized droplets.

Volvo Trucks has relied on field testing for the evaluation of lubricants for application in their engines. The initial Volvo VDS specification was upgraded first to VDS-2 and later to the current VDS-3 specification. In VDS-3 an engine lubricant is evaluated in a number of Volvo trucks over 3 drain periods of 100,000 km each. However, covering 300,000 km takes a considerable amount of time and the process of engine inspections and rating the various parts consumes a significant amount of resources. Engine oil performance screening would therefore be preferably done in an engine bench test of shorter duration and of better controlled operating conditions. Volvo Technology, I.S.P. Institute for Fuels and Lubes Testing and Chevron Oronite are very interested in correlating engine bench results with the outcome of VDS-3 field trials. In this paper, we evaluate a lubricant for 400 hours in a Volvo D12D engine run at I.S.P. Intermediate inspections were done at 200 and 300 hours.