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srm suite - Frequently Asked Questions |
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What is srm suite?
The srm suite is a sophisticated engineering tool for carrying out computations of fuels, combustion and emissions formation in an IC engine context.
How can it help me?
The software has five major features that distinguish it from conventional 1D or 3D fluid dynamics approaches
(a) it can solve for in-cylinder in-homogeneities (in contrast to 1D codes), enabling engineers to deal with composition/thermal stratification
(b) on account of its unique approach, the code is faster than 3D CFD, enabling engineers to carry out model parameter and design optimisations
(c) it includes state-of-the-art combustion chemistry, enabling engineers to solve for fuels, combustion characteristics, emissions and engine performance in a more robust way than previously possible.
(d) the gaseous emissions of NOx, CO and HCs are computed based on their formation: starting as a fuel molecule, during combustion and expansion. Soot emissions can also be computed using our detailed soot model, which solves for soot particle dynamics providing engineers with information such as particle size distribution including composition and morphology of soot aggregates.
(e) it uniquely facilitates inclusion of "emissions" within the domain of engine optimisation
Is it a 1D or 3D code?
Neither and both... the code combines the best features from both approaches, i.e. the speed of 1D, the predictive capabilities of 3D etc. but with the addition of state-of-the-art fuels, combustion and emissions modelling.
What does "srm" stand for?
Stochastic Reactor Model
What does "stochastic" mean?
It’s a statistics term for a process involving a sequence of observations each of which is considered as a random sample from a probability distribution. Stochastic fluctuations are inherent to any IC engine operation and need to be accounted in engine models.
What is a "stochastic particle"?
Each element of the probability distribution is termed a "stochastic particle". In a way a stochastic particle represents the air-fuel parcel. Depending on the application, between 50 and 500 stochastic particles are typically required to properly sample in-cylinder processes.
What is the basic methodology of srm suite?
The SRM Suite uses a probability density function (PDF) based approach that simplifies many of the most computationally expensive fluid-dynamic processes whilst maintaining much of the predictive capability of the 3D CFD codes. In general terms, this is achieved by intelligently "downsampling" the required number of grid points associated with CFD from tens-of-thousands down to a few hundred "stochastic particles" which best represent the in-cylinder mixture composition states.
The method retains the spatial information required to achieve a predictive model without incurring the computational overhead. The ensemble of the stochastic particles approximates the distribution of the in-cylinder properties such as the composition of chemical species and the temperature. The model is then solved to account for the influence of the processes such as fuel injection, combustion kinetics, turbulent mixing, piston motion and convective heat loss on the multi-dimensional PDF. The approach accounts for inhomogeneities in composition and temperature in the engine cylinder, which is crucial to the prediction of CO and unburned hydrocarbon (HCs) emissions.
Are there any user stories?
Yes. Visit the user stories page to see how our customers are using srm suite.
Do you have any publications describing the work?
The development of srm suite started at the University of Cambridge in 2000. It has featured at many research conferences and in many journal publications. For a complete list and for access to these please contact us directly at enquires@cmclinnovations.com.
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