Watch if you dare | Explaining my Master’s Thesis in Mechanical Engineering

hi friends today we’re doing a sit down video we haven’t done one of these in a while and what I really want to do is go through my master’s thesis because everyone always asks me what did I do what was my topic on and I feel like I should just address it make a full video about it and then put it in the past before we get started I want to say that this video is sponsored by deaf Mountain and if you don’t know Devin Melton is a coding school they teach tons of different development for web for iOS and they have many different locations in the States you can check them out in the link in my description thank you to Devin mountain for sponsoring this video boom so fast getting really good at that ok so going directly into my master’s thesis basically I’m kind of kind of give you the introduction of my master’s thesis which explains kind of everything we all know that renewable energies are gaining a lot of traction and they’re gaining a lot of funding and government subsidies because we’re pushing for renewables but if you know anything about renewables you also know that they’re very sporadic for example you only get electricity from solar panels when they can be charged with sunlight so that’s when there’s no clouds when it’s sunny outside so not at night etc etc for wind power it’s very sporadic you could have you know wind turbines spinning all the time and then as soon as there’s no when your turbines finish so renewable energy fluctuates a lot so despite a push for renewables we’re still going to continue burning fossil fuels that’s just the way it is right now we don’t have a better solution so now looking at fossil fuels particularly looking at natural gas which is not cool I personally believe we should all move away from coal coal is not very good so let’s talk about natural gas we’re gonna need to continue to burn fossil fuels in order to meet consumers energy demand when wind is not functioning and we can’t get energy from renewables we’re going to need to start up some gas turbines quickly to keep that energy demand constant for you know everyone everyone it’s trying to watch Netflix or cook and use their dishwasher whatever we’re going to need to meet that energy demand so a new novel combustion system that burns natural gas is called a sequential combustor so if you look at your PV thermodynamics diagram basically a normal combustor pumps in fuel burns the fuel and then releases that fuel it spins the turbine when the fuel expands and then the turbine generates electricity so a sequential combustor what it does is that instead of releasing that fuel air burnt combustion mixture after it combusts that mixture is still hot and the thing is that he contains a form of energy look heat is a form of energy it’s the lowest grade form of energy because it’s the hardest to convert to electricity or whatever what the sequential combustor does is it takes that heat from the combustion process and squirts in a little bit more fuel a little bit more air and then it combusts again if there doesn’t even need to be a spark or anything because the fuel air mixture is so hot from the first stage that if you’re just squirting a little bit more feel a little bit more air it combusts so then you have two flames in one gas turbine now this is state-of-the-art newest form of technology for gas turbine combustion systems and the reason it’s great is because it has super high operational and fuel flexibility and it’s more efficient so it can burn feel more efficiently now in the gas turbine industry usually what you want to do is you want to burn fuel at the super lean regime you don’t want to be wasting fuel when you can just squirt it in a little bit of fuel and get out the power that you want but the problem when you go to the fuel lean regime right now my hands are doing the equivalence ratio versus temperature Tyger him if you have an equivalence ratio of 1 which basically means you have perfect amount of fuel for the amount of air you have and together is in the perfect world if they mixed you would get co2 in water and you wouldn’t get any and nitrogen and you wouldn’t get any other byproducts so in a perfect world burning at an equivalence ratio of one would give you no other byproducts no other like NOx but that doesn’t happen you always have some sort of byproducts so what gas turbine companies do is they actually burn in a fuel lean regime so they have a lot of air and they just squirting a little bit of fuel why did I do this because they don’t want to waste fuel they don’t want to burn up all the fuel and they want to still generate electricity so that’s why they do it the problem is that when you go to this fuel lean regime you have a little bit of fuel for a lot of air so when you’re trying to mix that fuel in with the air you don’t get a homogeneous mixture before you burn that’s why a lot of companies you know spend a lot of time looking into different mixing methods like this is big field of research getting the perfect mixture of fuel and air is essential and when you have a little bit of fuel for a lot of air makes it more difficult to get this perfect mixture now why do we want this perfect mixture don’t worry I’m getting to my thesis project this is all tizen why do you want this perfect homogenous mixture so if you don’t have a homogenous mixture of like this amount of fuel like let’s say one part fuel to 10 part air if you don’t have this homogenous mixture everywhere you’re gonna have some parts of your fuel that have more fuel than air that have half fuel half air that have no fuel at all and when this happens when you when those little pieces of the mixture arrive to your flame front what happens is that certain parts of that mixture are gonna burn hotter than other parts because the closer you go to an equivalence ratio of one the hotter your flame will be so when I’m talking about the equivalent ratio of one again I’m talking about that perfect stoichiometric mixture of the perfect amount of fuel and the perfect amount of air that give you only co2 and water at the end of your combustion so if you have an in the homogenous mixture that reaches your flame front and parts of the fuel are burning hotter than other parts of the fuel you have a flame that’s burning and that is different temperatures at different parts of the flame so you have your a ménage mixture coming up to the flame front and now the flame is not the same temperature at every part why is that a problem so if you go to your ideal gas equation you know PV equals NRT the higher temperature you have the more pressure you have the higher temperature the flame is releasing in certain areas the higher pressure the flame is releasing in certain areas so now you have this different pressure fluctuations so having pressure fluctuations inside a gas turbine is dangerous because these pressure fluctuations are kind of like vibrations and they can couple with the geometry and material properties of the gas turbine and cause a feedback loop and then these vibrations can spiral out of control and in the most dangerous and serious cases the gas turbine can crack its components can crack and explode so that’s why it’s really important to minimize the vibrations and especially you want to make sure that the modes of the gas turbine so you’ll notice that there are different frequency ranges that you know if there’s some sort of in homogeneity inside of the flame and if it starts you know vibrating at a certain frequency the guest turbine can start vibrating at a first-served frequency maybe that’s 50 Hertz maybe that’s 200 Hertz maybe that’s however many you know 2,000 Hertz whatever you do not want to activate any of these natural frequencies of the combustion engine this is like I guess maybe I feel like I’m being clear if I’m not being clear let me know you know there are natural frequency modes if you have a string this long it will have a natural frequency of like two nodes 1/2 a wave you can do it in a way that it has two nodes or if you have a strong string this long it’ll be a different frequency and so that’s the same thing with gas turbine engines is that based on their geometry and their material properly produced and their size they will have different natural frequencies and these frequencies can be activated based on what the flame is doing so that’s what I was doing for my master’s thesis so this is called thermo acoustic coupling ok now you learn something new now thermal acoustic coupling basically has not really looked at in many cases the biggest field where it was investigated it was rocket engines so in the past rocket engines they would discover that they would explode and they couldn’t figure out why so for example for the Apollo 11 their engine was the Saturn 5 f1 now this engine had undergone 3200 full-scale tests and 2,000 of those full-scale tests were dedicated to solving the problem of thermo acoustics so it’s a big problem and it was mainly investigated in you know rocket engines but doing so many tests is super expensive especially for small companies or gas turbine companies or whatever doing these tests it’s expensive you can’t in the stand age rebuild and do tests on gas turbine or on rocket engines three thousand times what we do now is we use so that’s what I actually did in my master’s thesis what I did was I use safety program or it’s not really a program it’s like it was just a numerical solver so I used a numerical solver called a VDP and it’s not commercially available so you can’t get it basically I used this numerical solver and I created a mesh of not a real gas turbine but of like the test burner we have in our lab and I investigated thermo acoustics on this burner and the way I was doing that was that I was imposing an excitation in the first flame and then I was looking at what happened within the dynamics between the two flames if the pumping of the first flame affected the second flame or not that’s what I did I hope this was informative if you have any questions on my thesis you can ask them below if you would like my master’s thesis you can enter your email at the form below and I will email you might master’s thesis and you could read through it there are probably mistakes I don’t want to know if there are mistakes ok like I don’t care it’s submitted it’s done don’t email me back if I have mistakes I also my supervisor was a PhD student and — I also like my work fed into his work and together we published a journal article if you would like access to that journal article and to my master’s thesis you just enter your email in the form below and I will send that to you last thing is we’re doing a live stream on February 11 or 13 I’m not even sure anymore again it’ll be an AMA I’ll probably get some cake and eat cake while I answer your questions basically I just want to hang out I’m going to be in a new apartment by then so this week has been really stressful because I’m trying to pack here I’ll just show you I’m trying to pack up all of my crabs so here you’ll see I have this like my bags of clothes well actually this is just a full bag of shoes all of my clothes fit in there this is clothes that I can’t figure out what to do with them I then yeah I guess I have like an entire kayak right there that’s like my toiletries and then my aloe plants my lovely mellow plants I hope you liked this video if you liked it please give it a thumbs up do you want to see more please subscribe if you have any questions about my master’s thesis leave them in the comments below [Music]

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