Week 6:
After multiple dry tests, the wick is ready to be added to the interior of the tube. However, when planning for assembly, we did not consider how we might insert the wick in the most efficient manner possible. Since the mesh is not very rigid, many attempt to insert the mesh resulted in clogs and the mesh being destroyed. To fix this issue, we found a smaller tube that fits inside of ours and tightly wrapped the copper mesh around it. This method allows us to easily insert the mesh and only line the inside walls with the mesh, leaving an open chamber in the middle for the gas to flow through.
Week 5:
Before inserting liquid and the copper wire mesh wick into the heat pipe, the pipe's ability to transfer heat was tested. This data, shown below, was acquired to see the effect that an added wick and working fluid have on the thermal conductivity of the heat pipe.
Week 4:
After acquiring all the parts, except for the mesh which is still en route, assembly of the heat pipe cna begin. First, a 1/2 in. copper tube cap is soldered to one end, creating an air tight seal at the one end which will now be permanently attached. At the other end of the pipe, a 1/2 in. copper male adapter is soldered to the pipe, allowing a brass tube cap to be screwed on and removed with ease as shown in the figure below. Before screwing on the brass end cap, Teflon tape is wrapped around the male adapter to create an air tight seal between the brass cap and the male adapter. Without Teflon tape, the liquid inside of the tube would evaporate and escape right out of the end, resulting in a non-functional heat pipe.
Week 3:
After discussing and planning on where to acquire the parts necessary to construct this heat pipe, we decided to acquire all our materials from a local home depot. However, copper wire mesh is not avaliable at home depot and thus a 30-ft. roll of mesh was purchased from amazon and is expected to arrive within two weeks.
Week 2:
This week, we further planned for design and construction of the heat pipe. After further analyzing our initial design, we decided to add removable ends to our heat pipe to allow for the removal of liquid and wick from the inside of the tube.
Week 1:
The first week was spent researching and understanding heat pipes. To create a well-functioning heat pipe, external resources were very important in the planning process. From research this past week, the group could understand how heat pipes are constructed and work with devices to transport and spread heat.
Heat pipes are used in modern electronics to transfer thermal energy from a heat source to (very often) a heat sink, which allows the heat to be spread and then cooled by a fan or other cooling source. Heat pipes are vacuum sealed metal tubes containing an inner wick lining and a working fluid. One end of the pipe is then attached to a heat source causing the fluid in the pipe to heat up and evaporate. The vapor then expands and travels to the cooler end of the heat pipe where it condenses into the wick structure and travels back to the warm and as a liquid. This process is a constant cycle as shown in the figure below.
After multiple dry tests, the wick is ready to be added to the interior of the tube. However, when planning for assembly, we did not consider how we might insert the wick in the most efficient manner possible. Since the mesh is not very rigid, many attempt to insert the mesh resulted in clogs and the mesh being destroyed. To fix this issue, we found a smaller tube that fits inside of ours and tightly wrapped the copper mesh around it. This method allows us to easily insert the mesh and only line the inside walls with the mesh, leaving an open chamber in the middle for the gas to flow through.
Week 5:
Before inserting liquid and the copper wire mesh wick into the heat pipe, the pipe's ability to transfer heat was tested. This data, shown below, was acquired to see the effect that an added wick and working fluid have on the thermal conductivity of the heat pipe.
Table depicting the heat transfer in the heat pipe without a wick or liquid
Week 4:
After acquiring all the parts, except for the mesh which is still en route, assembly of the heat pipe cna begin. First, a 1/2 in. copper tube cap is soldered to one end, creating an air tight seal at the one end which will now be permanently attached. At the other end of the pipe, a 1/2 in. copper male adapter is soldered to the pipe, allowing a brass tube cap to be screwed on and removed with ease as shown in the figure below. Before screwing on the brass end cap, Teflon tape is wrapped around the male adapter to create an air tight seal between the brass cap and the male adapter. Without Teflon tape, the liquid inside of the tube would evaporate and escape right out of the end, resulting in a non-functional heat pipe.
Picture showing the end of the copper tube with a male adapter aTnd the brass end cap
After discussing and planning on where to acquire the parts necessary to construct this heat pipe, we decided to acquire all our materials from a local home depot. However, copper wire mesh is not avaliable at home depot and thus a 30-ft. roll of mesh was purchased from amazon and is expected to arrive within two weeks.
Week 2:
This week, we further planned for design and construction of the heat pipe. After further analyzing our initial design, we decided to add removable ends to our heat pipe to allow for the removal of liquid and wick from the inside of the tube.
Week 1:
The first week was spent researching and understanding heat pipes. To create a well-functioning heat pipe, external resources were very important in the planning process. From research this past week, the group could understand how heat pipes are constructed and work with devices to transport and spread heat.
Heat pipes are used in modern electronics to transfer thermal energy from a heat source to (very often) a heat sink, which allows the heat to be spread and then cooled by a fan or other cooling source. Heat pipes are vacuum sealed metal tubes containing an inner wick lining and a working fluid. One end of the pipe is then attached to a heat source causing the fluid in the pipe to heat up and evaporate. The vapor then expands and travels to the cooler end of the heat pipe where it condenses into the wick structure and travels back to the warm and as a liquid. This process is a constant cycle as shown in the figure below.
Choosing Materials:
When developing a materials list for the construction of a heat pipe, certain factors must be considered. An ideal heat pipe for this project transfers heat effectively at low temperatures, contains compatible combination of working fluid and material, and has a relatively low material cost.
The heat pipe must contain a compatible combination of working fluid and material to prevent the fluid from reacting with the interior of the pipe causing unwanted formation of gases, corrosion, and material transport. Many experiments have been conducted on all types of metals and fluids at different temperatures, thus determining ideal combinations for heat pipes at all different temperatures.
Since the heat pipe for this project only needs to withstand rather low temperatures for electronics cooling, a copper/water combination was selected. Both the pipe and the inner capillary structure (wire mesh) are both made of copper to prevent any problems.
When developing a materials list for the construction of a heat pipe, certain factors must be considered. An ideal heat pipe for this project transfers heat effectively at low temperatures, contains compatible combination of working fluid and material, and has a relatively low material cost.
The heat pipe must contain a compatible combination of working fluid and material to prevent the fluid from reacting with the interior of the pipe causing unwanted formation of gases, corrosion, and material transport. Many experiments have been conducted on all types of metals and fluids at different temperatures, thus determining ideal combinations for heat pipes at all different temperatures.
Since the heat pipe for this project only needs to withstand rather low temperatures for electronics cooling, a copper/water combination was selected. Both the pipe and the inner capillary structure (wire mesh) are both made of copper to prevent any problems.
Initial List of Materials:
- 1/2 in. x 10 ft. Copper Type M Hard Temper Straight
Pipe ($12.57 at Home Depot)
- 1/2 in. Copper Tube Cap ($0.27 at Hardware Supply)
- 16 oz. Lead Free Solder Paste Flux ($6.57 at
zoro.com)
- 8 oz. Bernzomatic Solid Wire Solder ($14.98 at Home
Depot)
- 12" x 24" Copper Mesh Sheet ($8.99)
No comments:
Post a Comment