Tuesday, February 17, 2015
Monday, February 16, 2015
Week 1
This week efforts were divided among three fronts: preliminary research, qualitative testing, and instrument drafting.
My preliminary research focused on different models of dynamic driven heat engines, to get a general grasp on how and why certain changes would affect the system. This was followed by qualitative testing to determine what parameter changes were worthy of consideration. I discovered that by heating the apparatus up lightly, thereby increasing the internal pressure, I could increase the steady state frequency slightly, until it dipped at higher temperatures.
I also researched and tested three separate frequency measurement systems: stroboscope, laser tachometer, and video analysis. First, by shining a strobe light on the instrument until it appeared stationary, I was able to find one of the modes of its frequency. This will be confirmed by slowed down video analysis of the light mill's motion. Lastly, I'm attempting to build a laser tachometer to measure the time between passes at steady state using a laser pointer and a photogate.
Special thanks to Dr. Haar and Dr. Hoffman for their amazing help
My preliminary research focused on different models of dynamic driven heat engines, to get a general grasp on how and why certain changes would affect the system. This was followed by qualitative testing to determine what parameter changes were worthy of consideration. I discovered that by heating the apparatus up lightly, thereby increasing the internal pressure, I could increase the steady state frequency slightly, until it dipped at higher temperatures.
I also researched and tested three separate frequency measurement systems: stroboscope, laser tachometer, and video analysis. First, by shining a strobe light on the instrument until it appeared stationary, I was able to find one of the modes of its frequency. This will be confirmed by slowed down video analysis of the light mill's motion. Lastly, I'm attempting to build a laser tachometer to measure the time between passes at steady state using a laser pointer and a photogate.
Special thanks to Dr. Haar and Dr. Hoffman for their amazing help
Thursday, February 12, 2015
Intro
I'm Alex Poelstra, a senior at BASIS Tucson North. My project attempts to model the turbulent flow in Crookes Radiometers to better predict their steady state, with the eventual goal of a large scale, energy harnessing model.
Crookes Radiometers, or Light Mills, are turbines that run off radiative heating. They consist of a spindle with a four-vaned rotor in a partially evacuated bulb, which rotates due to the diffusion of gas particles from the cold to hot edges.
Because the chamber is in a partial vacuum, it has a high Knudsen number, meaning particles particles will travel relatively far between collisions. This means the analysis must rely on statistical methods to simulate the system's motion rather than continuum mechanics.
My research is taking place at the U of A Physics and Atmospheric Science building, in Dr Manne's lab.The entirety of my proposal is available here.
Crookes Radiometers, or Light Mills, are turbines that run off radiative heating. They consist of a spindle with a four-vaned rotor in a partially evacuated bulb, which rotates due to the diffusion of gas particles from the cold to hot edges.
Because the chamber is in a partial vacuum, it has a high Knudsen number, meaning particles particles will travel relatively far between collisions. This means the analysis must rely on statistical methods to simulate the system's motion rather than continuum mechanics.
My research is taking place at the U of A Physics and Atmospheric Science building, in Dr Manne's lab.The entirety of my proposal is available here.
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