Hello, A change in allocation has been requested: Requester: dduke (Daniel Duke) Project: XRayFuelSpray Title: Fuel Injection and Sprays Studied Using X-Ray Diagnostics Description: Computational Fluid Dynamics using the OpenFOAM framework has been employed to simulate cavitating turbulent fluid flow in both simplified nozzles and diesel fuel injectors, with the purpose of supporting and informing x-ray radiography and phase-contrast measurements performed at the Advanced Photon Source. A number of state-of-the-art numerical solvers have been implemented in OpenFOAM; namely incompressible-liquid and fully compressible homogeneous relaxation cavitation models and more recently a noncondensible-gas fully compressible homogeneous relaxation cavitation model. These codes were developed by Schmidt et al at the University of Massachusetts-Amherst. In the last year, we have switched from using OpenFOAM’s built-in solvers for multiphase flow to a dedicated cavitation code (HRMFoam) developed by Professor David Schmidt. The homogeneous relaxation model (HRM) assumes that when vapor is present, the vapor and liquid are homogeneously mixed within the local cell, but are not at thermodynamic equilibrium. The equilibrium state is not computed using an equation of state but is instead determined from a lookup table formulated using NIST REFPROP data. The HRM model has successfully been employed to simulate the effect of varying gasoline-ethanol blended fuels in a cavitating polycarbonate nozzle, and the results were favorably compared to x-ray radiography measurements performed at the Advanced Photon Source. Further high-resolution large eddy simulations of the polycarbonate nozzles used at APS are need to be undertaken in the following year. Scalability of HRMFoam simulations is good up to approx. 72 processors (the capacity of our dedicated nodes). We need to run multiple simulations at various boundary conditions, thus the need for additional allocation beyond the use of the dedicated nodes. Several improved solvers are currently under development which over the next year will allow for the modeling of a non-condensible gas phase, to simulate the difference between a ‘submerged’ cavitating flow and a cavitating flow issuing into a gaseous environment, as is the case for fuel injection in engines. Compressible modeling is also being investigated through both HRM and also alternative compressible fluid solvers. Currently, HRM assumes the liquid phase to be incompressible. Although this has shown good results in comparison with experimental data, given the extremely high pressures involved in fuel injection (greater than 1500 bar) bulk compressibility of the fuel will not be insignificant. Further development is occurring within the OpenFOAM framework and we do not expect to need any additional software installed on Fusion to achieve these goals. Our allocation for the following year will need to be maintained at the current level to achieve the above goals. No increase in allocation is required. We expect that less than 1% of the allocation will be single-core jobs (of which most are file I/O and cleanup tasks at the start and end of parallel jobs). Current: undetermined amount Justification: 6*12 processor dedicated nodes have been purchased on FUSION to support these studies. Requested: 15000 A specific reason has been given: We have several simulations currently running on fusion and blues which need to be completed before the end of the current allocation period. We also need to run tests of a new build of OpenFOAM which will require some extra hours. As our allocation is almost exhausted for this period, we require extra core-hours for the current allocation period only, in order to complete these tasks. This needs to be approved and the final allocation amount decided upon. Thank You, The LCRC Accounts System