DWSIM Development Blog

I've managed to include some very useful features into the Optimizer. One of them is the ability to define constraints other than the independent variables. This is achieved by using barrier functions. The other is the inclusion of more numerical methods to solve the optimization problem through the DotNumerics library. You'll also have the option to define how the numerical derivatives will be calculated (2 or 4-point) and the barrier function multiplier, which defines how close to the constraints the optimizer will go.

I've also redesigned the interface in order to keep all information on the screen while solving the problem:

Two new unit ops are ready to deploy. They are:

- Component Separator, where you can specify component separation by absolute or relative (to the inlet stream) mass or molar flows. The energy streams completes the energy balance so you'll know how much energy is needed for the separation to occur.

- ISO 5167 Orifice Plate, that you can use to measure fluid flow. Because of the nature of the simulation engine, you can't calculate flow directly - you must use the Adjust or the optimizer to indirectly calculate flow by setting the pressure drop across the orifice as the objective function.

Next I'll implement a template system together with a new quick calculation feature, that will allow the user to calculate properties of a stream without creating a new simulation.

/Daniel

Build 3676 fixes a lot of bugs and adds important features to DWSIM. What's new:

- Napthali-Sandholm Simultaneous Correction (SC) method for rigorous column solving

- New Flowsheet color scheme, improved connector drawing algorithm, faster object drawing

- Expression support for the Sensitivity Analysis Utility

- Support for performance & system curves in the Adiabatic Pump

Click here to go to the downloads section.

I just implemented the pump curves feature in DWSIM. You'll be able to input head, power, efficiency, required NPSH pump curves and also build system curves using the sensitivity analysis utility, which was enhanced to support expressions as dependent variables.

The input values won't be limited to the simulation's unit set. Each curve has its own units and you'll be able to display the curves in the units you want to.

I'm planning to release the build with the new features and numerous bug fixes within the next days.

The next build will come with a number of bug fixes and improvements, with the most important being a series of optimizations in the rigorous colum model. You'll have more specification options, a new solving method (Naphtali and Sandholm Simultaneous Correction) and more control of the convergence process through new properties. Russell's IO method and the new one are now using four-point numerical derivatives. This scheme is a little slower than the usual 2-point differentiation, but greatly enhances the stability and reliability of the algorithm.

Drawing of the flowsheet is now much, much faster. I removed the antialiasing setting from the OnPaint method, but the quality remains the same.