Multi-criteria modeling of processes in a vaporjet condensation turbine ejector mixing chamber and its design

The paper presents recommendations on designing an efficient mixing chamber and regulating air and steam flows in the elements of a steam-jet apparatus based on the results of multi-criteria modeling of gas-dynamic processes. The paper also reveals the possibilities to provide a greater reduction in losses, air suction into the turbine and equipment repair costs compared to the cases when individual criteria for increasing the steam turbine equipment efficiency are used. The selected calculation methods, i.e. innovative (multi-criteria) and standard (standard), have been analyzed comparatively. As a result of the methods evaluation, the authors selected the following indicators: increased energy efficiency of the turbine due to the prevention of air suction in the turbine seals; increased efficiency of condensing turbines; reduced repair and maintenance costs for the turbine and ejector due to the ejector mixing chamber cross-sectional area optimization. Based on the comparison, the best results were shown with the multi-criteria modeling according to the indicated parameters, the coefficients of the flow rate, working steam consumption, size reduction and increase in service life from 20 to 40 years. The innovative method requires a larger number of optimality criteria and the regulation of process parameters and design geometry based on direct and feedback multi-criteria models. Using multi-criteria modeling, the authors determined the necessary composition of optimization parameters, i.e. the flow area of the designed mixing chamber, steam flow rate and thermodynamic flow parameters, as well as suction pressure.