Monthly Archives: March 2011

ASME Turbo Expo in Vancouver 2011

One of my New Year’s resolutions was to blog a bit more.  Clearly that isn’t going so well :-(.  One of my other resolutions from way back was inspired by Ben Goldacre, to talk a bit more in a non-dumbed down form about the work that Scientists do.  Now of course I’m actually an Engineer but since we appear to have successful finished the latest set of tests now seemed like a good time to talk about some of the fantastic work that my colleagues have produced and I will be talking about at ASME Turbo Expo in Vancouver.

In a fit of enthusiasm I decided to try and get three papers into the conference and thanks to the efforts of my co-authors have largely succeeded.  It was an enormous amount of work and I’m not sure I want to go through that again!  Anyway we ended up with three papers in the final programme:

  • THE EFFECTS OF IMPROVED STARTING CAPABILITY ON ENERGY YIELD FOR SMALL HAWTS (GT2011-45674)
  • TIME RESOLVED MEASUREMENTS IN THE DURHAM CASCADE (GT2011-45838)
  • PROFILED ENDWALL DESIGN USING GENETIC ALGORITHMS WITH DIFFERENT OBJECTIVE FUNCTIONS (GT2011-45836)

The second two refer to detailed measurements conducted inside the cascade and a design system to improve the performance of turbine blades using profiled endwalls.  These cover slightly more complicated concepts than the first one and I’ll see if I can get around to doing individual posts on each of them in turn – but no promises!

Anyway the first paper is about Horizontal Axis Wind Turbines or HAWTs for short.  (Normally I detest abbreviations but I seem to have one in a title there – oops)  This paper basically looks at how important starting performance is on the overall energy yield of a small wind turbine and according to our calculations it is quite important.

The paper is mainly based on a model of turbine start-up developed by Supakit using the MATLAB-SIMULINK modelling environment, we validated the model against some data kindly provided by  Professor David Wood at the University of Newcastle, Australia so we have some idea that the model produces outputs that are reasonable.  Essential the model uses a simple blade element momentum model of the wind turbine blade and a model of the various load types that the wind turbine might be connected with and enables us to calculate the energy yield under various wind conditions.

The picture below shows a figure from the paper showing how the revised blade designs (MX and MP) compare in terms of rotational speed to the original design (SG).

Start Up Curve for Original and Revised Designs

The headline result is that designing your wind turbine to start up more quickly can increase your energy yield by up to 40%.  However it can also reduce your energy yield under certain load types by around 4% so careful attention to the design is necessary.  One key message from the paper is that understanding more about the physics of the flow around the wind turbine at startup is a useful thing to do.