Solid-Fuel Gas Turbine

Solid-Fuel Gas Turbine

Idea Generation

What is this project about?

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Understanding the pros and cons of using solid fuels in a gas turbine.

2/9/21 New Goals: Obtain self-sustaining operation of the turbine. Once that is achieved, extract usable power from the engine (e.g. generator powering light bulb).

What do you want to get out of this project?

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Experience in gas turbine design and testing, and learn about the properties of different fuels burning under a high-pressure and high-temperature environment.

where did the skills go? we are taking skills out of the idea generation process, in an attempt to make projects more career-focused. If you want to get leveled-up for a project, share it with the appropriate guide or faculty member for feedback upon completion.

Guiding Question

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Why are commercial (and residential) gas turbines fueled by liquid fuel, as opposed to the seemingly more versatile solid fuel?

Exploration

Jan 12, 2021: The plan.
Jan 12, 2021: The plan.
Jan 18, 2021: The gas turbine partially attached to the firebox for fit testing. Shims can be seen holding the door tightly shut whilst the silicone gasket dries.
Jan 18, 2021: The gas turbine partially attached to the firebox for fit testing. Shims can be seen holding the door tightly shut whilst the silicone gasket dries.
Jan 19, 2021: A picture showing the gas turbine with its inlet pipes attached. The nozzles shown in the drawing are inside, but cannot be seen. The handwheel on the upper left of the turbine housing is connected to a valve at the back, which will be used as a shutoff by venting the pressure from the combustion chamber.
Jan 19, 2021: A picture showing the gas turbine with its inlet pipes attached. The nozzles shown in the drawing are inside, but cannot be seen. The handwheel on the upper left of the turbine housing is connected to a valve at the back, which will be used as a shutoff by venting the pressure from the combustion chamber.
Jan 19, 2021: The oil pressure compensator. This will use air pressure to maintain oil pressure to make the engine easier to operate, as I am using a hand-cranked oil pump. The oil will be pumped in from the left, and will partially fill the upright pipe. This will compress the air above the oil, thereby maintaining oil pressure on the bearings when the pump is not being cranked.
Jan 19, 2021: The oil pressure compensator. This will use air pressure to maintain oil pressure to make the engine easier to operate, as I am using a hand-cranked oil pump. The oil will be pumped in from the left, and will partially fill the upright pipe. This will compress the air above the oil, thereby maintaining oil pressure on the bearings when the pump is not being cranked.
Jan 19, 2021: The high-temperature silicone gasket. The oil pump can also be seen in the background on the bottom right.
Jan 19, 2021: The high-temperature silicone gasket. The oil pump can also be seen in the background on the bottom right.
Jan 20, 2021: The oil reservoir and pump holder, with the pump on top. This was my first time welding anything, and was sort of a practice piece (although still a necessary component). It was made from a steel bucket (clearly) with a "bridge" welded across the top, and a bung adapter for oil barrels welded in the middle. The oil pump is meant for dispensing oil from a 55-gallon drum, but I used it as an oil feed pump, because it was less expensive than an electric oil pump. It cannot be seen in this picture, but there is a one-way valve at the output of the pump (top) to prevent oil from flowing back into the reservoir when the system is pressurized.
Jan 20, 2021: The oil reservoir and pump holder, with the pump on top. This was my first time welding anything, and was sort of a practice piece (although still a necessary component). It was made from a steel bucket (clearly) with a "bridge" welded across the top, and a bung adapter for oil barrels welded in the middle. The oil pump is meant for dispensing oil from a 55-gallon drum, but I used it as an oil feed pump, because it was less expensive than an electric oil pump. It cannot be seen in this picture, but there is a one-way valve at the output of the pump (top) to prevent oil from flowing back into the reservoir when the system is pressurized.
Jan 22, 2021: The intake valve arrived!
Jan 22, 2021: The intake valve arrived!
Jan 22, 2021: The intake valve with a hole drilled in the bottom for the idle adjustment screw.
Jan 22, 2021: The intake valve with a hole drilled in the bottom for the idle adjustment screw.
Jan 22, 2021: Tapping threads in the hole for the idle screw. Brass is a very easily worked metal, because it is somewhat brittle, similar to cast iron.
Jan 22, 2021: Tapping threads in the hole for the idle screw. Brass is a very easily worked metal, because it is somewhat brittle, similar to cast iron.
Jan 22, 2021: The intake valve mounted to the engine, showing the intake horn (front of valve) and the idle adjustment screw (protruding from the left side). The screw has a spring on it to prevent it from loosening due to vibration.
Jan 22, 2021: The intake valve mounted to the engine, showing the intake horn (front of valve) and the idle adjustment screw (protruding from the left side). The screw has a spring on it to prevent it from loosening due to vibration.
Jan 22, 2021: A view looking down the intake horn, showing the idle screw holding the intake valve gate partially open.
Jan 22, 2021: A view looking down the intake horn, showing the idle screw holding the intake valve gate partially open.
Jan 22, 2021: First starting attempt; too many leaks to self-sustain chamber pressure. The largest leak is at the back where the hot side pipe joins the firebox. The leaking gap can be seen glowing from the hot gases escaping. This has since been welded shut, and I will try to start it again soon.
Jan. 28, 2021: A more detailed plan, showing the names of the components used, as well as a realistic, non-schematic view of the engine itself. The ash extraction port has been omitted for now, as to minimize possible leaking points for testing.
Jan. 28, 2021: A more detailed plan, showing the names of the components used, as well as a realistic, non-schematic view of the engine itself. The ash extraction port has been omitted for now, as to minimize possible leaking points for testing.

Jan. 28, 2021: Later today I'm going to get parts for, and make a new firebox door, as the original door is too warped and leaky, and all attempts to seal it (silicone, rope gasket, etc.) have failed. A simple metal-on-metal seal will be far more reliable.

Jan 28, 2021: I built a door! It is as of yet untested, but it already seems to make a far better seal than the original warped cast-iron door that it came with.
Jan 28, 2021: I built a door! It is as of yet untested, but it already seems to make a far better seal than the original warped cast-iron door that it came with.
Feb 12, 2021: The housing for the power turbine. I also made a bearing housing that threads onto the end, but I don't have a picture of it yet.
Feb 12, 2021: The housing for the power turbine. I also made a bearing housing that threads onto the end, but I don't have a picture of it yet.
Feb 14, 2021: I made a preheater blower to supply air to the fire while it is warming up, making it easier to start. The valve will be closed during operation to seal the firebox.
Feb 14, 2021: I made a preheater blower to supply air to the fire while it is warming up, making it easier to start. The valve will be closed during operation to seal the firebox.
Feb 14, 2021: A view of the underside of the firebox, showing where the preheater air line attaches.
Feb 14, 2021: A view of the underside of the firebox, showing where the preheater air line attaches.
Feb 25, 2021: Here are some of the new parts I made over the last few days. From left to right, the shaft bushing that will support the end of the shaft inside the turbine housing. Next is a collar with a grub screw, which will be welded to the turbine so I can use the grub screw to hold the turbine to the shaft. Then comes the turbine wheel blank, which will be divided into 8 sections (like a pizza). Each section will then be cut down about 3/4 inch, and twisted to form the turbine blades. Last is the rear bearing housing, which is the back half of an old electric motor pressed onto the end of a 2 inch pipe t-joint. The side port in the t-joint (on the backside, not seen in the picture) might be used as a water injection port for cooling the rear bearing, as it will have no oil flow to cool it.
Feb 25, 2021: Here are some of the new parts I made over the last few days. From left to right, the shaft bushing that will support the end of the shaft inside the turbine housing. Next is a collar with a grub screw, which will be welded to the turbine so I can use the grub screw to hold the turbine to the shaft. Then comes the turbine wheel blank, which will be divided into 8 sections (like a pizza). Each section will then be cut down about 3/4 inch, and twisted to form the turbine blades. Last is the rear bearing housing, which is the back half of an old electric motor pressed onto the end of a 2 inch pipe t-joint. The side port in the t-joint (on the backside, not seen in the picture) might be used as a water injection port for cooling the rear bearing, as it will have no oil flow to cool it.
A closer view of the first three of the above parts, more clearly showing the grub screw in the collar (centre).
A closer view of the first three of the above parts, more clearly showing the grub screw in the collar (centre).
Feb 25, 2021: Side quest: Make a dirt furnace for case-hardening the steel bushing and shaft to increase their service life.
Feb 25, 2021: Side quest: Make a dirt furnace for case-hardening the steel bushing and shaft to increase their service life.
Feb 25, 2021: Firing the dirt furnace for the first time to glaze the inside for strength. This was done without the parts to be hardened inside, it is just for the furnace. The glazing is achieved naturally by the silica in the clay and dirt the furnace is dug out of. Air is supplied from the blower on the left through a sloped underground passage that enters the furnace at the bottom left of the chamber, about 1 foot underground. Shown running on a mixture of coal (dug from my own backyard) and charcoal.
Feb 25, 2021: Firing the dirt furnace for the first time to glaze the inside for strength. This was done without the parts to be hardened inside, it is just for the furnace. The glazing is achieved naturally by the silica in the clay and dirt the furnace is dug out of. Air is supplied from the blower on the left through a sloped underground passage that enters the furnace at the bottom left of the chamber, about 1 foot underground. Shown running on a mixture of coal (dug from my own backyard) and charcoal.

What will it take for you to complete this project?

Use the table below to set your own timeline for deliverables, keep in mind when your final work product is due at the end of the cycle.

Work Product Deliverables

MilestoneDateDone
Gather/make components
Assembly and testing
January 28, 2021
Work Product due
January 29, 2021

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