Pulse Detonation
From Colleen:
Pulse detonation is pretty interesting because it's really the first time they have thought about something really different than normal combustion for turbine engines (Brayton Cycle) that seems feasible. The biggest challenge right now for PDE (pulse detonation engines) is size vs output...which is definitely a problem for aircraft but not for power plants. Also, I guess for power plants they aren't running on a PDE but they are using the technology to increase efficiency. This is from teh GE global research blog:
"During the course of our research, we have found a more near term application for this technology that is helping power plant boilers run more efficiently. In fact, GE Energy introduced a product, called Powerwave+™ this past February. Powerwave+ harnesses shockwaves created through the pulsed detonation process and directs them at problem areas in the boiler. It does a tremendous job dislodging buildup and cleaning the boiler, so that it runs more efficiently.
Because it helps run boilers more efficiently, less energy is required to produce power. If you have Powerwave+™ in a coal-fired boiler, you can greatly reduce the amount of coal needed to produce power. That in turn can help reduce the carbon footprint, which is good for the environment. "
They are talking about the next step being to use a PDE to make power however for a "small power plant"....maybe for our ship applications.
And more on efficiency and how PDE's work from the blog...
"As the name implies, a PDE uses "detonations" to burn the fuel in a more explosive and more efficient manner compared to your usual steady deflagration flame. A deflagration is the normal way to burn fuel… you see it everywhere… a fireplace, a candle burning, inside an internal combustion engine, and inside today's aircraft engines. It's also what powers the world in today's large megawatt scale gas turbine based powerplants. A detonation, on the other hand, looks nothing like a deflagration. A detonation is a shock wave travelling at Mach 5 (5 times the speed of sound!!) that ignites the fuel-air mixture as it passes. The combustion products are at higher pressure (this is a key difference from a deflagration) and that translates into a more efficient conversion of the chemical energy stored in the fuel into useful work.
The reason why I am so excited about PDE's is that we can potentially reduce the amount of fuel burned by a whopping 5%!! That might not sound like much, but in the aircraft propulsion world a 1% improvement translates into hundreds of millions of dollars of savings per year!! Considering that present day deflagration-based gas turbine engines have already been highly optimized over the past 50 years (a 0.2% improvement is considered a major breakthrough)… "
Norm's take: Thats pretty damn sweet. I have always liked simple blow fuel up in a tube jets, as they operate efficiently and have a multitude of uses. The idea of a rotating gattling gun style engine... just think about that for a second. Of course, cutting fossil fuel use, saving money etc would be great side effects. The example below is not likely to be the future of travel.
http://www.autobloggreen.com/2008/05/15/for-those-with-a-death-wish-pulse-jet-powered-bicycle/
Pulse detonation is pretty interesting because it's really the first time they have thought about something really different than normal combustion for turbine engines (Brayton Cycle) that seems feasible. The biggest challenge right now for PDE (pulse detonation engines) is size vs output...which is definitely a problem for aircraft but not for power plants. Also, I guess for power plants they aren't running on a PDE but they are using the technology to increase efficiency. This is from teh GE global research blog:
"During the course of our research, we have found a more near term application for this technology that is helping power plant boilers run more efficiently. In fact, GE Energy introduced a product, called Powerwave+™ this past February. Powerwave+ harnesses shockwaves created through the pulsed detonation process and directs them at problem areas in the boiler. It does a tremendous job dislodging buildup and cleaning the boiler, so that it runs more efficiently.
Because it helps run boilers more efficiently, less energy is required to produce power. If you have Powerwave+™ in a coal-fired boiler, you can greatly reduce the amount of coal needed to produce power. That in turn can help reduce the carbon footprint, which is good for the environment. "
They are talking about the next step being to use a PDE to make power however for a "small power plant"....maybe for our ship applications.
And more on efficiency and how PDE's work from the blog...
"As the name implies, a PDE uses "detonations" to burn the fuel in a more explosive and more efficient manner compared to your usual steady deflagration flame. A deflagration is the normal way to burn fuel… you see it everywhere… a fireplace, a candle burning, inside an internal combustion engine, and inside today's aircraft engines. It's also what powers the world in today's large megawatt scale gas turbine based powerplants. A detonation, on the other hand, looks nothing like a deflagration. A detonation is a shock wave travelling at Mach 5 (5 times the speed of sound!!) that ignites the fuel-air mixture as it passes. The combustion products are at higher pressure (this is a key difference from a deflagration) and that translates into a more efficient conversion of the chemical energy stored in the fuel into useful work.
The reason why I am so excited about PDE's is that we can potentially reduce the amount of fuel burned by a whopping 5%!! That might not sound like much, but in the aircraft propulsion world a 1% improvement translates into hundreds of millions of dollars of savings per year!! Considering that present day deflagration-based gas turbine engines have already been highly optimized over the past 50 years (a 0.2% improvement is considered a major breakthrough)… "
Norm's take: Thats pretty damn sweet. I have always liked simple blow fuel up in a tube jets, as they operate efficiently and have a multitude of uses. The idea of a rotating gattling gun style engine... just think about that for a second. Of course, cutting fossil fuel use, saving money etc would be great side effects. The example below is not likely to be the future of travel.
http://www.autobloggreen.com/2008/05/15/for-those-with-a-death-wish-pulse-jet-powered-bicycle/
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