Reducing entropy generation by volumetric heat transfer in a supersonic two-phase steam flow in a Laval nozzle

Simultaneous effects of inlet stagnation pressure and heat transfer to the water vapor condensing flow of supersonic laval nozzle

“…Based on the presented diagrams and the results of the previous study by the authors [6], it is concluded that volumetric heating of the convergent section of a Laval nozzle can improve the wetness parameters, and increase the efficiency and stability of the flow. However, the investigations also reveal that these positive effects are accompanied by an undesirable side effect, i.e.…”

“…For better understanding, the total amount of heating in each case and total latent heat released in adiabatic flow is shown in table.3. Regarding reference [6] and first part results it is known that heating the convergent section with fixed inlet stagnation pressure causes abate of Supersaturation ratio, degree of supercooling, postpone the maximum of them and finally decrees the nucleation rate. On the other hand this heating make some mass flow rate leakage that can be recovered by little increasing of inlet stagnation pressure.…”

“…In this research on the following of previous work of these authors [6] the flow is studied non adiabatic In this paper initially the semi -analytical, Eulerian -Lagrangian model is explained, then different nucleation rate expressions are studied and suitable one is selected and finally regarding the presenting model the effects of volumetric heat transfer and inlet stagnation pressure variation are investigated simultaneously.…”

A blackbox optimization of volumetric heating rate for reducing the wetness of the steam flow through turbine blades

“…The importance of volumetric heating in reducing the performance losses of steam turbines is studied in recent years. Mahpeykar et al [16] applied volumetric heating to the convergence part of a one-dimensional convergentdiverging nozzle and studied the steam condensation flow parameters as well as the entropy generation. They observed that by adding appropriate volumetric heating, the nucleation rate and supercooling temperature could be significantly reduced.…”

Numerical Simulation on Condensing Flow of Water Vapor of Wet Natural Gas Inside the Nozzle

“…The effect of the expansion rate on the steam condensing flow through a converging-diverging nozzle was studied numerically (Nikkhahi et al, 2010). The steam condensing flow was modeled through the Laval nozzles at low and high inlet pressures by means of the single-fluid model (Mahpeykar et al, 2011;Shooshtari et al, 2013;Dykas et al, 2011). The Eulerian/Eulerian approach was adopted for modeling the condensing steam flow, and the simulation was conducted on the commercial ANSYS FLUENT platform (Yousif et al, 2013).…”