Adrian Ilinca

WIND POTENTIAL ASSESSMENT OF QUEBEC PROVINCE

The paper presents the development of a comprehensive wind atlas of the Province of Quebec. This study differs from previous studies by 1) use of a standard classification index to categorize the wind resource, 2) extensive review of surface and upper air data available for the Province to define the wind resource, and 3) integration of available wind data with the topography of the Province.

Study of a Hybrid Wind-Diesel System with Compressed Air Energy Storage

The electricity supply in remote areas around the world uses mostly diesel generators. This method, relatively inefficient and expensive, is responsible for the emission of 1.2 million tons of greenhouse gas (GHG) annually, only in Canada. Some low and high penetration wind-diesel hybrid systems (WDS) have been experimented in order to reduce the diesel consumption. The use of a high penetration system together with compressed air energy storage (CAES) it is a viable alternative to improve the overall percentage of renewable energy and reduce the cost of electricity. In this paper we compare different technical solutions for the CAES system and choose the one that optimize the performance and the cost of the overall system. While in this extended abstract only a superficial description of this system is introduced, detailed results of the simulation will be presented in the complete paper. This new design conducts to the increase of diesel power and efficiency, to the reduction of fuel consumption and GHG emissions, in addition to economies on the maintenance and replacement cost of the diesels.

Numerical Study of Flow Around Iced Wind Turbine Airfoil

Abstract This investigation analyzes the impact of ice accretion on the aerodynamic coefficients of a wind turbine airfoil. Three blade sections located at different radial positions were analyzed. Numerical simulations were conducted over a two-dimensional clean and ice-accreted NACA 63–415 airfoil at various angles of attack. The results for pressure, lift, and drag coefficients were inspected at an angle of 13° for which experimental data were available. The streamlines around the clean and iced airfoil were also inspected, in order to evaluate the ice impact on lift and drag. The simulations were carried out using the commercial package FLUENT, and turbulence was addressed with the SST k - ω) model.

New Roughness Computation Method and Geometric Accretion Model for Airfoil Icing

This paper presents recent developments in wet and dry ice accretion simulation at AMIL (AntiIcing Materials International Laboratory), in a joint project with CIRA (Italian Aerospace Research Center). This paper introduces an analytical model to calculate the surface roughness and the remaining, runback, and shedding liquid water mass on an airfoil surface. Three analytical formulations are used to calculate the local roughness height based on the maximum height that a bead can reach before moving and the wave height on a water film. A mass balance is used to determine the remaining and runback water masses when the water state and the maximum bead height are known. The water shedding mass is determined using a simple mass model. A new method is used to build the accreted ice surface on the airfoils. It uses the bisection of the angle between adjacent panels to determine ice shape. The new roughness computation method and the geometric model generate the complex ice shapes observed experimentally and the results agree well with icing profiles obtained in wind tunnel experiments.

Analysis and Mitigation of Icing Effects on Wind Turbines

Precipitation, atmospheric and in-cloud icing affect wind turbine operation in various ways, including measurement and control errors, power losses, mechanical and electrical failures and safety hazard. Anti-icing and de-icing strategies are used to minimize these effects. Many active and passive methods are in development but few are available on the market. Active heating of blades is the most tested, used and reliable way to prevent icing effects. It is used in parallel with passive hydrophobic coating to lower energy consumption. Precise icing evaluation of the site should be done during the assessment phase to evaluate the necessity and benefits of installing anti-icing and/or de-icing system. This evaluation shall continue during operation in order to optimize production and avoid component failure related to icing events. Multiple anemometry in combination with relative humidity measurements is a cheap and reliable icing detection method during assessment while the use of ice sensors and the power curve method is recommended during operation. Most of the wind turbines operating in cold climates are facing icing events, but very few of them are equipped with blade de-icing systems, and few studies were performed and published on the characteristics of these systems. Technical difficulties due to cold climate conditions have occurred for most of the existing projects in Quebec. Thus, icing simulations were carried out in the refrigerated wind tunnel of the Anti-icing Materials International Laboratory (AMIL) at Universite du Quebec a Chicoutimi (UQAC). The effect of icing conditions observed at the wind farm in Murdochville, Quebec, Canada has been assessed on a 0.2 m NACA63-415 blade airfoil. The shape and mass of the ice deposit on a wind turbine airfoil has been measured, as well as the lift and drag force on the iced airfoil. Scaling was carried out based on the 1.8 MW–Vestas V80 wind turbine technical data, for three different radial positions and two in-fog icing conditions measured at the Murdochville wind farm in the Gaspe Peninsula. For both icing events, the mass of ice accumulated on the blade airfoil increased as we move to the tip of the blade. In wet regime, glaze formed mostly near the leading edge and on the pressure side. It also accumulated by run-off on the trailing edge of the outer half of the blade. In dryregime, rime mostly accreted on the leading edge and formed horns. For both icing events, when glaze or rime accreted on the blade airfoil, lift decreased and drag increased. A load calculation using the blade element theory shows that drag force on the entire blade becomes too large compared to lift, leading to a negative torque and the stop of the wind turbine. Torque reduction is more significant on the outer third of the blade. Setting up a de-

Techno-Economic Analysis of Different Energy Storage Technologies

Overall structure of electrical power system is in the process of changing. For incremental growth, it is moving away from fossil fuels major source of energy in the world today to renewable energy resources that are more environmentally friendly and sustainable [1]. Factors forcing these considerations are (a) the increasing demand for electric power by both developed and developing countries, (b) many developing countries lacking the resources to build power plants and distribution networks, (c) some industrialized countries facing insufficient power generation and (d) greenhouse gas emission and climate change concerns. Renewable energy sources such as wind turbines, photovoltaic solar systems, solar-thermo power, biomass power plants, fuel cells, gas micro-turbines, hydropower turbines, combined heat and power (CHP) micro-turbines and hybrid power systems will be part of future power generation systems [2-8].

Assessment of turbulence models for flow simulation around a wind turbine airfoil

This investigation focuses on the application of the computational fluid dynamics tool FLUENT to the study of flows over the NACA 63-415 airfoil at various angles of attack. With the aim of selecting the most suitable turbulence model to simulate flow around ice-accreted airfoils, this work concentrates on assessing the prediction capabilities of various turbulence models on clean airfoils at the large angles of attack that cause highly separated flows to occur. The study was undertaken by conducting simulations with the one-equation Spalart-Allmaras (SA) model, the two-equation RNG k-e and SST k-ω models, and the Reynolds stress model (RSM). Domain discretization was carried out using general quadrilateral grids generated with GAMBIT, the FLUENT preprocessing tool. Comparisons were made with available experimental data.

Assessment of Two-Equation Turbulence Models and Validation of the Performance Characteristics of an Experimental Wind Turbine by CFD

The very first step in the simulation of ice accretion on a wind turbine blade is the accurate prediction of the flow field around it and the performance of the turbine rotor. The paper addresses this prediction using RANS equations with a proper turbulence model. The numerical computation is performed using a commercial CFD code, and the results are validated using experimental data for the 3D flow field around the NREL Phase VI HAWT rotor. For the flow simulation, a rotating reference frame method, which calculates the flow properties as time-averaged quantities, has been used to reduce the time spent on the analysis. A basic grid convergence study is carried out to select the adequate mesh size. The two-equation turbulence models available in ANSYS FLUENT are compared for a 7 m/s wind speed, and the one that best represents the flow features is then used to determine moments on the turbine rotor at five wind speeds (7 m/s, 10 m/s, 15 m/s, 20 m/s, and 25 m/s). The results are validated against experimental data, in terms of shaft torque, bending moment, and pressure coefficients at certain spanwise locations. Streamlines over the cross-sectional airfoils have also been provided for the stall speed to illustrate the separation locations. In general, results have shown good agreement with the experimental data for prestall speeds.

Fuel consumption evaluation of an optimized new hybrid pneumatic–combustion vehicle engine on several driving cycles

In this paper, we describe an optimization followed by a fuel-saving evaluation of a new concept of a hybrid pneumatic–combustion engine that can be obtained by modifying a conventional internal combustion engine without developing a new cylinder head. Until now, most studies on the pneumatic hybridization of internal combustion engines have dealt with a two-stroke pure pneumatic mode. The few concept studies that have dealt with a hybrid pneumatic–combustion four-stroke mode required a supplementary valve to be added to charge compressed air in the combustion chamber. This heavy modification cannot be carried out by simply adjusting an existing internal combustion engine because a new cylinder head should be developed. It is therefore not logical to suggest this concept as an option in vehicle powertrains to reduce fuel consumption. Moreover, those studies focus on spark-ignition engines; there are reasons to think that their concepts might not work adequately for diesel engines. Our concept is capable of making a diesel engine operate under two-stroke pneumatic motor modes, two-stroke pneumatic pump modes and four-stroke hybrid modes, without requiring an additional valve in the combustion chamber. This fact constitutes our study’s strength and innovation. The evaluation of our concept is based on ideal thermodynamic cycle modeling. The optimized valve actuation timings for all modes lead to generic maps that are independent of the engine size. The fuel economy is calculated based on the new European driving cycle and on the assessment and reliability of transport emission models and inventory system urban and rural cycles.

3-D Multiple-level simulation of free surface flows

A 3-D multiple-layer model to describe and compute free surface flows has been applied to rivers and seashore parts. Vertical convective fluxes and shear stress at the interface are kept in the x-y momentum equation. The hydrostatic pressure of the top layer, is taken into account. The flow is calculated via a finite volume numerical scheme. The solver is based on Roes Flux Difference-Splitting (FDS) method. The spatial discretization uses triangular elements as the basic control-volume cells. Data obtained from references, analytical solutions and real configurations have been used to evaluate the performance of the proposed method. The numerical scheme has been shown to be capable of predicting the behavior of Ekmans classical surface layer or of a simple tide wave fixed on an open boundary of a rectangular domain, for example. The evolution of a tidal constituent on the St.Lawrence estuary is also presented.