User:Rshrikanth

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Shrikanth Ranganadham

Proposal : http://socghop.appspot.com/gsoc/student_proposal/private/google/gsoc2010/shrikanth/t127083559873

Mentor : Krishnan Chittur

Goals

ASCEND's thermophysical property database is presently available in files written using ASCEND syntax. This data is open and new data can added without any requirement of recompilation.But browsing data in difficult in this form. This Project aims at migrating present database in .a4l file to *.db format. SQLite can be employed for this database migration. Also it would be necessary to have certain interface to load database from an ASCEND model. After successful migration, tests are needed to formulated and carried out to make sure that the property formulations worked as expected.

Work done

Added 9 components into FPROPS database.

Patch for gibbs free energy in helmholtz function

Present work

RADAU5

Introduction

Radau5 codes are based on runge kutta implicit methods. The present native integrators LSODE and IDA are based on backward difference formula(BDF) where as newly added DOPRI5 and RADAU5 are based on single step methods of runge kutta are simply called march forward methods as they don't depend on previous values of y. RADAU5 codes are capable of integrating stiff ordinary differential equations and differential algebraic equations and there general accuracy of order 5. For further reading please refer Solving ordinary differential equations part 2 by E.Hairer and G.Wanner where solving procedure as well code are discussed.

work done

Primary wrapper for integrator is finished and is available in trunk version.

Integrator performance against van der pol problem (stiff ode) has been satisfactorily tested.

Further work

More rigorous testing required to be performed.

Present wrapper supports solving ODE's. Although DAE's can also be solved but approach doesn't make use of native ability of RADAU5 and order of accuracy would be smaller. Extending wrapper support to make use RADAU5's DAE solving ability is in proposed further work.

Codes

HDPE reactor model

http://ascendcode.cheme.cmu.edu/viewvc/code/branches/shrikanth/models/kchittur/shrikanth/HDPE.a4c?revision=3176&view=markup

PYTHON script for integrating above model http://ascendcode.cheme.cmu.edu/viewvc/code/branches/shrikanth/models/kchittur/shrikanth/HDPE_integrate_ida_ctrl.py?view=markup