In the last 30 days

• Open/close Improved, low-input establishment and management of contour-hedges for unpredictable, hot climates

  Torsten Mandal 2009 IOP Conf. Ser.: Earth Environ. Sci. 6 412031 Tag this article

  Article References Full text PDF (459 KB)

  This article was submitted without an abstract, please refer to the full-text PDF file.

• Open/close Medical applications of electromagnetic fields

  Henry C Lai and Narendra P Singh 2010 IOP Conf. Ser.: Earth Environ. Sci. 10 012006 Tag this article

  Article References Full text PDF (558 KB)

  In this article, we describe two possible applications of low-intensity non-ionizing electromagnetic fields (EMF) for the treatment of malaria and cancer, respectively. In malaria treatment, a low-intensity extremely-low frequency magnetic field can be used to induce vibration of hemozoin, a super-paramagnetic polymer particle, inside malaria parasites. This disturbance could cause free radical and mechanical damages leading to the death of the parasite. This concept has been tested in vitro on malaria parasites and found to be effective. This may provide a low cost effective treatment for malaria infection in humans. The rationale for cancer treatment using low-intensity EMF is based on two concepts that have been well established in the literature: (1) low-intensity non-thermal EMF enhances cytotoxic free radicals via the iron-mediated Fenton reaction; and (2) cancer cells have higher amounts of free iron, thus are more susceptible to the cytotoxic effects of EMF. Since normal cells contain minimal amount of free iron, the effect would be selectively targeting cancer cells. Thus, no adverse side effect would be expected as in traditional chemotherapy and radiation therapy. This concept has also been tested on human cancer cell and normal cells in vitro and proved to be feasible.

• Open/close Parametric design of a Francis turbine runner by means of a three-dimensional inverse design method

  K Daneshkah and M Zangeneh 2010 IOP Conf. Ser.: Earth Environ. Sci. 12 012058 Tag this article

  Article References Full text PDF (1.10 MB)

  The present paper describes the parametric design of a Francis turbine runner. The runner geometry is parameterized by means of a 3D inverse design method, while CFD analyses were performed to assess the hydrodymanic and suction performance of different design configurations that were investigated. An initial runner design was first generated and used as baseline for parametric study. The effects of several design parameter, namely stacking condition and blade loading was then investigated in order to determine their effect on the suction performance. The use of blade parameterization using the inverse method lead to a major advantage for design of Francis turbine runners, as the three-dimensional blade shape is describe by parameters that closely related to the flow field namely blade loading and stacking condition that have a direct impact on the hydrodynamics of the flow field. On the basis of this study, an optimum configuration was designed which results in a cavitation free flow in the runner, while maintaining a high level of hydraulic efficiency. The paper highlights design guidelines for application of inverse design method to Francis turbine runners. The design guidelines have a general validity and can be used for similar design applications since they are based on flow field analyses and on hydrodynamic design parameters.

• Open/close Flow characteristics and performance evaluation of butterfly valves using numerical analysis

  S Y Jeon et al 2010 IOP Conf. Ser.: Earth Environ. Sci. 12 012099 Tag this article

  Article References Full text PDF (1.39 MB)

  The industrial butterfly valves have been applied to various fields that transport fluid in volume, especially water supply and drainage pipeline for flow control. The butterfly valves in various shapes are manufactured, but a fitting performance comparison is not made up. For this reason, we carried out numerical analysis of some kind of butterfly valves for water supply and drainage pipeline using commercial CFD code FLUENT, and made a comparative study of these results. Also, the flow coefficient, the loss coefficient, and pressure distribution of valves according to valve opening rate were compared each other and the influence of these design variables on valve performance were checked over. Through flow around the valve disk, such as pressure distribution, flow pattern, velocity vectors, and form of vortex, we grasped flow characteristics.

• Open/close Analysis of the Kaplan turbine draft tube effect

  L Motycak et al 2010 IOP Conf. Ser.: Earth Environ. Sci. 12 012038 Tag this article

  Article References Full text PDF (1.20 MB)

  The aim of this paper is to present information about possible problems and errors which can appear during numerical analyses of low head Kaplan turbines with a view to the runner – draft tube interaction. The setting of numerical model, grid size, used boundary conditions are the interface definition between runner and draft tube are discussed. There are available data from physical model tests which gives a great opportunity to compare CFD and experiment results and on the basis of this comparison to determine the approach to the CFD flow modeling. The main purpose for the Kaplan turbine model measurement was to gather the information about real flow field. The model tests were carried out in new hydraulic laboratory of CKD Blansko Engineering. The model tests were focused on the detailed velocity measurements downstream of the runner by differential pressure probe and on the velocity measurement downstream of the draft tube elbow by Particle Image Velocimetry method (PIV). The data from CFD simulation were compared to the velocity measurement results. In the paper also the design of the original draft tube modification due to flow improvement is discussed in the case of the Kaplan turbine uprating project. The results of the draft tube modification were confirmed by model tests in the hydraulic laboratory as well.

• Open/close Impellers of low specific speed centrifugal pump based on the draughting technology

  C Hongxun et al 2010 IOP Conf. Ser.: Earth Environ. Sci. 12 012018 Tag this article

  Article References Full text PDF (954 KB)

  The authors analyzed the reasons of low efficiency under different operation condition based on the performance test and CFD numerical simulation approach. And the analysis focuses on the relationship between pump efficiency and inner flow characteristics. In order to improve the internal flow and increase efficiency of the pump, some draughting methods of improving the internal flow structure have been proposed, and some new impellers were developed by these methods. The main geometric parameters of the impellers, such as diameter, width and installation of the size, were consistent with the original impeller. The experimental results show that the efficiency of new impellers was improved significantly. The authors' work has opened up a new direction for further improving the efficiency of the low specific speed centrifugal pump.

• Open/close RASS sound speed profile (SSP) measurements for use in outdoor sound propagation models

  S G Bradley et al 2008 IOP Conf. Ser.: Earth Environ. Sci. 1 012005 Tag this article

  Article References Full text PDF (454 KB)

  The performance of outdoor sound propagation models depends to a great extent on meteorological input parameters. In an effort to improve speed and accuracy, model output synthetic sound speed profiles (SSP) are commonly used depending on meteorological classification schemes. In order to use SSP measured by RASS in outdoor sound propagation models, the complex profiles need to be simplified. In this paper we extend an investigation on the spatial and temporal characteristics of the meteorological data set required to yield adequate comparisons between models and field measurements, so that the models can be fairly judged. Vertical SSP from RASS, SODAR wind profiles as well as mast wind and temperature data from a flat terrain site and measured over a period of several months are used to evaluate applicability of the logarithmic approximation for a stability classification scheme proposed by the HARMONOISE working group.

• Open/close Steady-state capabilities for hydroturbines with OpenFOAM

  M Page et al 2010 IOP Conf. Ser.: Earth Environ. Sci. 12 012076 Tag this article

  Article References Full text PDF (1.36 MB)

  The availability of a high quality Open Source CFD simulation platform like OpenFOAM offers new R&D opportunities by providing direct access to models and solver implementation details. Efforts have been made by Hydro-Québec to adapt OpenFOAM to hydroturbines for the development of steady-state capabilities. The paper describes the developments that have been made to implement new turbomachinery related capabilities: Multiple Frame of Reference solver, domain coupling interfaces (GGI, cyclicGGI and mixing plane) and specialized boundary conditions. Practical use of the new turbomachinery capabilities are demonstrated for the analysis of a 195-MW Francis hydroturbine.

• Open/close Development of Pelton turbine using numerical simulation

  K Patel et al 2010 IOP Conf. Ser.: Earth Environ. Sci. 12 012048 Tag this article

  Article References Full text PDF (1.51 MB)

  This paper describes recent research and development activities in the field of Pelton turbine design. Flow inside Pelton turbine is most complex due to multiphase (mixture of air and water) and free surface in nature. Numerical calculation is useful to understand flow physics as well as effect of geometry on flow. The optimized design is obtained using in-house special optimization loop. Either single phase or two phase unsteady numerical calculation could be performed. Numerical results are used to visualize the flow pattern in the water passage and to predict performance of Pelton turbine at full load as well as at part load. Model tests are conducted to determine performance of turbine and it shows good agreement with numerically predicted performance.

• Open/close Impacts of 21st century sea-level rise on a Danish major city – an assessment based on fine-resolution digital topography and a new flooding algorithm

  Jesper Erenskjold Moeslund et al 2009 IOP Conf. Ser.: Earth Environ. Sci. 8 012022 Tag this article

  Article References Full text PDF (2.98 MB)

  This study examines the potential impact of 21st century sea-level rise on Aarhus, the second largest city in Denmark, emphasizing the economic risk to the city's real estate. Furthermore, it assesses which possible adaptation measures that can be taken to prevent flooding in areas particularly at risk from flooding. We combine a new national Digital Elevation Model in very fine resolution (~2 meter), a new highly computationally efficient flooding algorithm that accurately models the influence of barriers, and geospatial data on real-estate values to assess the economic real-estate risk posed by future sea-level rise to Aarhus. Under the A2 and A1FI (IPCC) climate scenarios we show that relatively large residential areas in the northern part of the city as well as areas around the river running through the city are likely to become flooded in the event of extreme, but realistic weather events. In addition, most of the large Aarhus harbour would also risk flooding. As much of the area at risk represent high-value real estate, it seems clear that proactive measures other than simple abandonment should be taken in order to avoid heavy economic losses. Among the different possibilities for dealing with an increased sea level, the strategic placement of flood-gates at key potential water-inflow routes and the construction or elevation of existing dikes seems to be the most convenient, most socially acceptable, and maybe also the cheapest solution. Finally, we suggest that high-detail flooding models similar to those produced in this study will become an important tool for a climate-change-integrated planning of future city development as well as for the development of evacuation plans.