As fluid flows through a conventional wind or hydro turbine, it slows from losing energy to extraction from a turbine and spreads out to a wider area. This results in a loss of turbine efficiency. In order to exploit wind or water flow power more effectively, it was suggested to place the turbine inside a system of specially designed airfoils ('a flow booster'). One part of the booster ('a nozzle') improves the turbine performance by speeding up the flow acting on the turbine blades. The other part of the accelerating system ('a diffuser') creates a field of low pressure behind the turbine which helps to draw more mass flow to the turbine and avoid the loss of efficiency due to flow deceleration. The flow booster accumulates the kinetic energy of the flow (e.g. river flow or wind) in a small volume where the smaller turbine can be installed. Another possible application of the booster could be the improvement of wind turbine efficiency during low wind period. The present paper also discusses the possibility of kinetic energy accumulation by the use of several accelerating systems of different sizes-the smaller one can be installed inside the bigger one. It helps to accumulate even more kinetic energy on the turbine blades. We call this method the kinetic energy cumulation. Lab and field experiments and CFD simulations of shrouded turbine demonstrate significant increase in velocity in comparison of those for conventional (bare) turbines.

Methods of laboratory modeling of 2D water flows in a rectangular channel are developed. The flow is produced in a vertical tube of a rectangular cross section when water flows through the hole in the bottom of the tube. In the setup, a short-term (up to ∼15 s) laminar water flow with a velocity up to about 18 cm/s is produced. The methods for recording the flow velocity and the type of the flow past models of various shapes are developed

In the Intermissions…, pp. 177-186 (1998) No AccessCOLLISIONLESS DISPERSION OF AN IONIZED CLOUD INTO A HOMOGENEOUS MAGNETIZED PLASMAA. I. GOLUBEV, A. A. SOLOV'EV and V. A. TEREKHINA. I. GOLUBEV, A. A. SOLOV'EV and V. A. TEREKHINhttps://doi.org/10.1142/9789812815941_0028Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: In this report the problem of a cylindrical explosion in rarefied plasma with the Alfven Mach number much higher than 1 is solved numerically on the basis of a one-dimensional hybrid model in which the ion motion is described by the Vlasov equation, while the electron component is described as massless fluid. The qualitative pattern of the developing flow and the mechanism of interaction of the dispersing cloud with magnetized external plasma is investigated in a fair detail. Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Vol. 5, pp. 33-42, 1978. Original article submitted September 20, 1977. FiguresReferencesRelatedDetails In the Intermissions…Metrics History PDF download

In doing research on the turbulent mixing (TM) of two gases different in density, it is of great interest to study experimentally the 3D density distribution pattern of chemically nonreactive gases in the TM zone. For this purpose, noncontact and, particularly, optical techniques to obtain experimental data may be attractive. This article discusses the possibility of using pulsed laser interferometry in this application. Based on this technique, the experiment should result in the mixture density distribution integrated along the light path. Requirements for high-quality interference patterns have been analyzed in application to typical experimental conditions, to show that they may be produced with specific restrictions set on the mixture constitution. Generally, the TM zone has no symmetry. Therefore, the problem of reconstructing 3D density distributions (TDD) of gases can be solved by sufficiently providing many TM zone integral projections (or aspects). It is technically difficult and expensive to achieve this large number of aspects ( N > 10). Therefore, it is essential that a reconstruction method be selected to allow the solution of the problem with the least possible number of aspects. Given that the experiment data are incomplete, the reconstruction methods that are based on the concept of maximum data entropy did well. Information a priori about the solution to be sought for an isobaric gas mixture is that its each constituent has invariable density. Thus, a functional data entropy can be defined that is similar to Fermi gas in statistical physics. An algorithm has been suggested for reconstruction as a modified maximum-bounded entropy procedure (Bashurin et al. 1995). This makes reasonable good reconstruction achievable even with as few aspects as N = 4. Experiments on the study of TM of a propane jet in air using a four-aspects laser interferometer were provided and reconstruction of propane concentration distribution was conducted. The results allow determination of the TM zone spectral characteristics.