Search results

Filters

  • Journals
  • Date

Search results

Number of results: 6
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

Optimization of vane positions in a mechanical draft wet-cooling tower is presented in this paper. The originally installed, equally spaced, vanes produced non-uniform air velocity distribution reducing the performance of the fill of the cooling tower. A 2D CFD model of the tower has been created. The model has then been used to determine the objective function in the optimization procedure. The selected objective function was the standard deviation of the velocity of air entering the fill. The Goal Driven Optimization tools of the ANSYSWorkbench 2.0 have been used for the optimization and the ANSYS Fluent 13.0 as a flow solver. The optimization allowed reduction of the objective function and producing a more uniform air flow.
Go to article

Authors and Affiliations

Adam Klimanek
Tomasz Musioł
Adam Stechman
Download PDF Download RIS Download Bibtex

Abstract

The presented work gives an overview on simulation and experimental results of the power supply parameters’ influence on DBD discharge uniformity. The proposed study is about the use of quasi-pulsed, power electronic power supply and a saturable inductor in series with the discharge cell [1]. The simulation results are presented with a parallel DBD reactor model with linear critical voltage distribution. A more uniform current waveform is observed, however, due to small reactor capacitances no streamer formation could be verified in calculations. An experimental test stand was prepared with a double dielectric barrier discharge arrangement. The experimental results are presented with regard to the electrical oscilloscope waveforms and ICCD camera imaging. A more homogenous plasma was observed in the case of saturable inductor with saturation current set at the point of discharge formation. Two possible mechanisms are connected with this phenomenon – inductive element current support during discharge and/or current rise-time limitation [1].

Go to article

Authors and Affiliations

Marcin Hołub
Download PDF Download RIS Download Bibtex

Abstract

Refined Schwarz-Christoffel (SC) conformal transformations allow us to perform reliable quantitative evaluation of the accuracy of local computation of electric and magnetic fields with limited effort, which can be useful to complement well known comparisons of global results. In this paper some examples are presented for mesh point potentials obtained by means of finite difference (FD) methods, but it is possible that similar considerations will be useful in the case of finite element methods (FEM) or meshless computations too.

Go to article

Authors and Affiliations

Eugenio Costamagna
Download PDF Download RIS Download Bibtex

Abstract

An integrated Z-source inverter for the single-phase single-stage grid-connected photovoltaic system is proposed in this paper. The inverter integrates three functional blocks including maximum-power-point-tracking, step-up/down DC-side voltage and output grid-connected current. According to the non-minimum-phase characteristic presented in DC-side and the functional demands of the system, two constant-frequency sliding-mode controllers with integral compensation are proposed to guarantee the system robustness. By using two controllers, the effects caused by the non-minimum-phase characteristic are mitigated. Under the circumstance of that the input voltage or the grid-connected current changes suddenly, the notches/protrusions following the over-shoot/ under-shoot of the DC-bus voltage are eliminated. The quality of grid-connected current is ensured. Also, a small-signal modelling method is employed to analyze the close-loop system. A 300W prototype is built in the laboratory. A solar-array simulator (SAS) is used to verify the systematic responses in the experiment. The correctness and validity of the inverter and proposed control algorithm are proved by simulation and experimental results.

Go to article

Authors and Affiliations

Z. Chen
X. Zhang
J. Pan

This page uses 'cookies'. Learn more