The study of converging-diverging nozzle for improving the impulse momentum of cross flow turbine in a bio-micro power plant

Abstract

Nozzle is the one important component in a power cycle plant that transfers heat enthalpy to kinetic energy for rotating power turbine. The biomass has specific characteristics heating value comparing to conventional fuel, and it is one of the renewable energy. The flow characteristics flow trough cross area nozzle plays important role that absorbs maximum drop enthalpy and momentum flux to drive turbine blade. The study of converging-diverging steam nozzle design was conducted using CFD modelling for improving a micro power bio-energy cross-flow turbine model. The objective of this work was to analyze the improvement of momentum flux by simulating a converging-diverging nozzle. A mathematical modelling of compressible flow using EES® tools was developed as well, to calculate the suitable dimension of inlet, throat, and outlet as computational domain. The flow characteristic parameters such as distribution of pressure, temperature, and velocity were compared analytically to find the good approximation of momentum flux for turbine demand. For pressure ratio 0.5 and temperature 200 ?C of steam fluid, the maximum velocity of 1.3 Ma and mass flow 0.978 kg/s (3.52 ton/hour) were occurred. Flux could be increased by making larger cross sectional area.