Three years gone, Six months to go… (almost anyway)

I remember being told by my Mum that the road to hell is paved with good intentions. And all my good intentions at the time last year to blog bi-weekly definitely have made my path to the hot place a little bit more easy. So, in penance and to try blogging again here we go.

A lot has happened since September last year, and I'm not quite sure how best to do this, so I've decided to give a bit of photo diary of the last 12 months to give a taste of what's been going on both in PhD-world and my own.

In October/November I was working on the stability analysis of parallel inverters, using small signal stability analysis, the results of the analysis match the simulations relatively well, hopefully these will also match the experimental work as well. Below is the pole-zero plot for the parallel inverters.

Pole-zero plot for parallel inverters

I met one of the founders of Learning Planet, Justin Wickham, in London to discuss the pico hydro scheme they are looking at. You can see more of the area Learning Planet are in here or have a look on their website www.learningplanet.org.uk.

 

The School in Dhawa renovated by Learning Planet

My cousin Helen got married at the end of October, so we headed over to Ireland to celebrate.

Helen and me at her wedding

I helped on the sound desk again with Horfield Theatre Company for their October pantomime, Franky Panky and had a lot of fun - with innuendo and a lot of childish humour. I'm getting a little bit better on the sound, although every so often the wrong person's mic would be turned up… A fun fun week nonetheless!

Franky Panky's Poster

I had a "cruise" to Bruges with my little sister, which was fun - especially all the chocolate!

Me and a bear in Bruges

During November and December I wrote a paper on the experimental turbine work I'd been doing, and submitted it to the Journal of Applied Energy at the beginning of January. It was finally accepted in June, and published here in July! The paper that I presented at WREC was also published in Renewable Energy Journal in July this year as well, here.

A figure from the Applied Energy journal, the slug of water that's ingested by the turbine in one rotation

In the last weekend of November, Hannah and I went to Salisbury to celebrate two years. We had a fun couple of days and saw Stonehenge, the Cathedral, Avebury and the Uffington White Horse.

The Stone Circle at Avebury

I spent Christmas with my parents and sisters, which was great.

With my family at Mount Edgecombe

Back in the lab, I started working on an improved control system to try and reduce any current spikes when the two inverters connected together so that switches won't go bang when the inverters are connected to a grid. This improved control did what it was supposed to in the simulation.

Reduced current spikes on paralleling inverters

I had another family wedding in Ireland, my cousin Gillian got married in early February and Hannah and I headed over for the weekend. Unfortunately snow made our journey back delayed… (I blame Gillian's sister, Jenny, who flew back with us!)

Gillian and Alex's wedding

I found an IEEE conference in Kathmandu that would take place in late September, known as ICSET. I wrote two papers for this conference, one on the turbine testing and the other on a simulation of a off-grid pico hydro network, submitting them by the end of March, which were approved. I'm off to Nepal on the 17th September, which is going to be amazing.

A simple model of an off-grid pico hydro network

I also attended and presented at the EWB research conference at UCL at the end of March, adding to the stress at the time, but really enjoyed it and was interested to hear some of the other projects going on in the EWB universe.

AC grid with distributed generators connected with inverter front ends

After submitting the papers, Hannah and I went off to India for two weeks, and had the most fantastic time. We spent a week in Kerala and a week in Bangalore, and had some amazing experiences, spending a night on a houseboat, riding on an elephant, and visiting some beautiful parts of the countryside.

On a houseboat in Alleppey, Kerala

On returning from India, I started to build some electronics, starting with a simple inverter, four switches and an inductor-capacitor filter. I built a simple control circuit in analogue components to control the output current to a reference sine wave from a signal generator. The circuit managed to produce a relatively good output.

Inverter Mk1 and Output

At the end of April, Hannah and I went to see one of my favourite bands, Feeder, in Cardiff. They were absolutely amazing. Enough said.

At the Feeder gig

By the beginning of May, it was time to do 'Living Below the Line' again (see last years version here). We raised money for MRDF and this time, there were a good 10 of us that did it.

Pasta Dinner during Live Below The Line

Once the original inverter worked, I built a second checking it worked with the basic controller, and then used a real time controller called dSPACE which can use MATLAB models to control things, allowing quick changes to be made to the model and be able to see the result of it. Both inverters worked controlled by the dSPACE which was great.

Parallel Inverters with dSPACE

The Olympic Torch came to Bristol in May, and we went down to the Harbourside to see it. The city was buzzing, and we had a fantastic time watching it arrive.

Olympic Torch arriving in Bristol

I ran a quick tour of the Hydrolab for the University of Bristol's Open Day in June, and showed some of the potential new students around and demonstrated the turbine rig. By the end of the day, my voice was hoarse, but had talked to many hundreds of people.

Turbine rig running

Obviously with London holding the Olympics, I wasn't going to miss going to see some events. We went to see the Beach Volleyball on Horseguards Parade and some Hockey in the Olympic Park, just a most fantastic experience.

Beach Volleyball at Horseguards Parade

Once each of the inverters worked individually, I connected them together, to see how they would work in parallel. They synchronised without blowing up, which was always good, and now in my work I'm trying to improve the performance of the system.

Parallel inverters

Every year Bristol holds an International Balloon Fiesta in Ashton Court, on the outskirts of Bristol. We went to the Nightglow, where the balloons light up to music, and saw a mass take off with Tim, who had come over from New Zealand.

Balloons at the Nightglow

We had a few days in Cornwall, camping. It rained, well it was Cornwall after all, but had a few nice and sunny days, especially down on the Lizard and ate some rather tasty ice-cream too…

Lizard Lighthouse in the sunshine!

A couple of weeks later we returned to Cornwall for a school friend's wedding. Again it rained, and it didn't really let up this time. Argh. Still, we enjoyed an ice-cream in the rain.

Hannah eating an Ice-cream in the rain at Lanhydrock

As well as the Olympics, we also got some tickets for the Paralympics, this time for the swimming, athletics and also saw some judo and table tennis. If anything, we enjoyed this more than the Olympics, the atmosphere was just incredible.

The long jump in the Olympic Stadium

And straight from the Paralympics we headed to the Small is Festival 2012. I had been asked to do a little workshop on pico hydro, and so designed a workshop to build a little crossflow turbine and test it, the workshop went really well and I had a very inspirational weekend. And it didn't rain!

The workshop at Small is Festival

So, hopefully now you're all about caught up with me and my life. I'm really sorry it's taken so long to do this, but I hope I'll be a bit more regular. Not long to go with the PhD now either. Times are scary and fun!

SAM

Testing Times

First things, I'm going to Sweden in May! Woo! My paper was accepted - I was a little bit concerned that they wouldn't agree with my changes and responses, but no further feedback.

At the beginning of March was the EWB Conference in the Royal Academy of Enginnering, London. The conference was split into 2 sections, education and research. I wasn't really initially interested in the education part, I didn't care that much about it. However, I had to attend one of the talks and so went to one called "I don't want to change light-bulbs; I want to change the world!", mainly because I liked the title. However, it was very good. It talked about problem based learning, using complex questions that have no correct answer. I thought it was a very interesting way to learn, very similar to how you work. I presented in the energy panel, which also featured work from Solar, biogas, biofuel briquettes and smokeless stoves. It was great to see a broad spectrum of energy research, but all trying for the same goal. The other panel I attended was the industry panel, mainly to listen to Jon Leary and listen to the presentation about the desert fridge. The papers for them can be found here and here. It was a great day, I managed to meet a lot of people to discuss some ideas, although didn't get as much feedback on my project as I'd hoped. I stayed in London for the Saturday after the conference, Hannah came up and we went to Tower Bridge Exhibition - a fantastic exploration about how Tower Bridge works - before heading to the West End to watch The Lion King - The Musical, which was absolutely amazing.

Tower Bridge Old Engine Room

Along with Katie Cresswell-Maynard from EWB, we gave a talk to the IMechE, Bristol and Bath branch. Katie talked about the need for engineers to help in global warming and poverty alleviation. Some of the statistics really made me think. Over 1.5 billion people (around 20% of the world's population) without proper sanitation. 900 million people without access to drinking water. Then over the next 20 years our requirement for water, food and electricity are going to be increasing with population growth. It's a big issue. I think the thing that got me the most that 1.5 million people a year are dying from preventable diseases. That to me is just wrong. After all those sobering statistics, I stood up and talked about my project, the technology I'm looking at and the benefits. I think the thing that brings it home to me is some of the interviews that we carried out in Nepal with PEEDA. There, people were so grateful that they had received electricity, it enabled them to work at night-time, not have to pay for kerosine and have clean and safe lighting as well as TVs and radios. (Video taken from PEEDA's website.)

I think I gave a good talk, and I met a lot people who wanted to chat about the project and has given me some more motivation about going forward.

I've been progressing with the testing. It's been quite slow initially, trying to understand how the rig can be operated. First I looked at how to capture all the water exiting the turbine, so the water didn't go over the floor. After some searching, I found a huge tank in the back of the Hydrolab, which could sit the turbine rig in. Any splashing water would then be captured by the tank, and pumped out by the submersible pump.

The rig in the large tank

The next task was to test the jet to ensure it was stable and a constant diameter. As can be seen in the photo below, the jet looked good across all heads.

The jet stability

With the jet stable, I did a check to see how much the head could be varied. From my specification, the head needed to be able to vary between 0.5m and 3.5m head. The head is adjusted by using two valves in the pipe run, one controlling the main head, then the second takes off any excess water, reducing the pressure. The flow is measured to calculate the head at the nozzle using velocity head. We could vary the head down to 1.0m, but below that, the flow rate became too low and the flow meter was unable to measure it. However, it was decided that this was not a real problem. We increased the head to maximum to see what it would be. However, as the static pressure increased behind the nozzle, this became too much for it and blew the nozzle off the pipe. Then followed a scene similar to those in slapstick films where I attempted to hold on to a flailing hose which was intent on covering the Hydrolab with water. After that I fixed the nozzle in with glue and put two grub screws in to fix it onto the pipe, which would increase the strength of the joint. I also resolved to only push it as far as 3.5m head!

Once this was done, the the testing began. Being a aero/mechanical engineer, I have never really used oscilloscopes before, so it took me a while, and a lot of help (thanks Niall and Gyorgy) to learn how to use it properly. However, once this was overcome, then I managed to get some readings for torque and speed out of the turbine. I was able to do a couple of runs at a constant head, varying the speed of the turbine as well, by varying the electrical load on it. From this I've got some initial curves which I need to now compare with my model.

The modelling has been more tricky than I had initially imagined. The flow inside the Turgo turbine is highly complex, with a jet impinging on the Turgo cups. There are several different forces at play, 3D flow effects and factors due to the shape of the cups and angle which the jet impacts it. All of which means that the next step from a simple 2D model is highly complex, and would normally include some sort of CFD. However, I have no intention of doing any CFD as this would not allow the model to be simply run for lots of different cases easily. Also, the CFD model would be severely complex as well. So, I've been reading up on how Pelton wheels are modelled to see if I can use any of the techniques there to match with the Turgo.

Outside of the PhD, I have been doing some more work with HTC. In the last week of February they did a evening of songs from the shows, films and TV. There was minimal stage management work to do on this occasion, so instead I found myself sat behind the sound desk. There, I had to balance the sound of the show between the backing tracks and the singers. I had never done anything like it before and found it very difficult to do, however, by the end of the run I found myself getting better. The show was a great success and we managed to have a full house most nights.

At the beginning of March I was very tired. I decided that I needed a short break, and so spent a week in Scotland visiting some friends and my cousin. I went to Aviemore, where a friend works in an outdoors shop. There I went for a bit of a wander around and climbed a hill behind the town. From Aviemore, I drove over the Cairngorms, by the slightly dubious ski centre at Lecht, and headed to the granite city of Aberdeen to stay with my cousin Linda, and her husband Dave. I had a brilliant time with them, just relaxing, reading, watching films and talking. I was amazed at the length of Aberdeen's beach, which stretched several miles up the coast. Hundreds of miles out to sea from Aberdeen are the oil and gas rigs, making Aberdeen Europe's self proclaimed 'energy capital'. Although you can't see the rigs themselves, you do know they are there. Very regularly, helicopters fly overhead ferrying workers to and from the rigs. In the bay by Aberdeen several supply ships are sat, waiting for their next delivery. It was quite fun just to sit and watch the world go by.

A view from the hill behind Aviemore

In Aberdeen, I also met a friend of mine from my undergraduate days, Keith. Keith was a engineer on the helicopters, doing the maintenance. As he did shift work, I was lucky enough to see him for a couple of days and we headed into the mountains again to have a look at the Victorian trail - around 60 miles from Aberdeen is Balmoral, the Queen's summer residence. As we headed deeper into the Cairngorms, the weather closed in around us, and then the snow came. It was fun to be driving in the snow again (or to be exact, driven in the snow), but I wasn't looking forward to making my way back to Aviemore again in it. So, when the time came to head back, I went the long way round, avoiding all possible snow related problems. Phew. One relieved Sam.

The snow falling as we head along the Victorian Trail up the river Dee

The next month sees me doing more testing and hopefully getting further along the road with my model. I need to start working on the next phase of the project as well soon, looking at the electrical side of things. Hopefully that can start more in earnest soon too!

SAM

p.s. This is a picture of Aviemore station, which has always been somewhere I've wanted to go. When we were little, we used to play a game called The Great Game of Britain, where you would get sent to Aviemore station and could normally only leave if you rolled a six...

Aviemore Station! My life is now complete...

It works!

For the last month I have been working in our Hydrolab installing the turbine and the associated pipework. I'm not the best at installing things, but I'm quite pleased with the pipe run. I've fitted the system onto the downpipe from a tank 40ft (12.5m) above the lab. The plan of the pipe is in the drawing below:

Plan for pipe installation

I made a series of brackets with Unistrut and Dexion metal frames to support the pipe. I cut the pipe and assembled it dry to make sure that everything fitted before gluing everything together. The PVC pipe glue stinks. It is the most awful smell, even in the large space of the Hydrolab. After a day of gluing pipes together I had a really bad headache, but everything fitted as planned. There were a couple of problems where the glue dried before I could get the pipe to fit snuggly into the fittings, but I managed to adjust some of the brackets to allow for the slight changes in length.

The next step was to silicon up the joints to make them watertight, before checking the pipework for leaks by putting water through the system. There are several valves between my pipe run and the 40ft tank supply. One of them had been shut for a long time, and would not open. Myself and the lab technician, Jack, spent 2 days soaking the valve in WD40, heating it up and hitting it with a large hammer. Finally it cracked open and we were able to pressurise the pipework. There were just 4 small leaks in the pipe, which I was quite impressed with.

Pipework

After plugging the leaks and allowing the silicon to dry off we did another leak check, and the leaks were pretty much sealed - just a couple of small drops of water were coming out. So, now was the moment of truth. Connecting everything together to see if the turbine would work. The last year has really come down to this, the choice of turbine and design of the rig - what would happen if it didn't work. I hadn't really thought about that. I connected up the turbine to the flexible pipe from the end of the pipe run, switched on the oscilloscope to look at the output from the torque transducer and current sensor (used to measure the speed of rotation of the turbine) and then slowly cracked open the control valve.

With a rushing of water, the pipes slowly filled with water and the nozzle pressurised. Finally the nozzle exploded into life, directing water at the turbine, and the turbine began to spin. Across on the oscilloscope a trace was visible from the current and the torque. The excess water fell into the little water tank and then was pumped away by a little submersible pump. The only real problem was that the tank obviously wasn't up to the task that I required of it, water splashed out and all over the Hydrolab floor. But it worked! A video and a couple of photos of the first run can be seen below.

Turbine running with the water splashing

Oscilloscope trace (top torque, lower - current)

Video of first run

So now, the testing begins, and trying to match the model and test results…

EWB Conference

Last year I displayed a poster at the EWB research conference. This year, I was asked to present a paper on the Energy Panel about my work so far. This will be in the beginning of March at the Royal Academy of Engineering, London. So I spent a couple of days writing a paper to describe the work I've been doing. I'm looking forward to the conference, to get feedback on the work I've done so far and see what people think about the direction I've gone it, especially as it will be the first time I'm presented my work to people outside the university.

I received comments on the WREC paper I submitted before Christmas. Most of the comments were insignificant, and we got a great score on the paper. This was fantastic, and after a couple of small alterations to the paper, I resubmitted it again. I should hear back about the paper in the middle of February, whether it's been accepted or not.

It's going to be a fun couple of months, finally getting some testing to do!

SAM

Easter Holidays

So, for the last few months I've been working on finding a way of selecting a turbine. This has meant going back to basic theory and looking at how turbines work, which has been very useful. It has reminded me of the fun I had in my undergraduate times, we did experiments with Pelton wheels, jets, flow measuring devices and so on. It also has brought some things to attention, why propeller turbines are normally used at low head, the problems with Pelton and Turgo wheels when the jet is slow. Here's some pictures of turbines if you have no idea what is what...

Pelton Wheel

Turgo Wheel

Crossflow

Francis Turbine

Propeller Turbine

Waterwheel

Archimedes Screw

The PhD is in association with Engineers Without Borders - UK (www.ewb-uk.org). So, I joined EWB for their annual research conference at the Royal Academy of Engineering in London, where I presented a poster about my research. The poster didn't say too much about the solution of my research problems, but I think describes the problem quite well. It was interesting to listen to the other EWB researchers, what they were up to, their motivations and so on, and also see who was up to anything hydro-like.

EWB Poster

This term, I've helped out in my first undergraduate lab. My supervisor was doing a series of lectures on Electrical Product Design, and part of this included a lab on designing a solar powered motor - the product itself wasn't the most useful, the process is the important part. So I helped out in the lab. I was rather scared, as I still really hadn't done much practical electronics apart from building the SMPS (see last time's blog), and I knew they would ask questions that I couldn't answer. But, it wasn't too bad, I managed to answer most things, and with the help of George, my lab-mate, we survived.

I had an afternoon out in Bristol with a friend, which as many people know is the home of the engineering genius Brunel. I met the man himself at his iron ship, the SS Great Britain.

Brunel and Me (yes, I needed a haircut)

I've also booked my tickets to go back to Nepal again. I'm going to arrive there exactly one year after leaving last time, 16th April, which is a bit of a coincidence. I'm really looking forward to seeing all my friends there and just having a relax. The plan is to do a bit of research into small scale hydro as well. I'm very very excited.

For now

SAM