Chemical Heat Driven Turbine



Abstract


The freshmen students could possibly build a computer-controlled turbine using their LEGO sets. Two streams of chemical reactants could be controlled in such a manner that the energy produced by the reaction would be constant (or responsive to human commands to change). The energy given off by the reaction would then be used to drive a turbine. Engineering skills for this project include: chemistry, thermodynamics, and feedback-type control systems.


Basic description

The main object of the LEGO lab is to provide an experience in which freshmen can see how their engineering "intuition" can be quantified and expanded by means of basic engineering concepts. (This implies that the lab handout may be the most important part of the lab.) The project to be designed should also be chosen so as the development could use some of the skills of the designers: namely, the skills of a senior mechanical, electrical, and chemical engineer.

A chemically-driven turbine would fulfill these goals. First of all, if the project designers do their job well, it will be possible for the freshmen to do the project. The students would build their system and see it work. A good pre-lab handout would wrap up the project by giving the freshmen an engineering description of what was happening in the reaction, the steam process, and the control systems.

The project itself would consist of several sections. Two tanks would hold the reactants. Pipes would transport the reactants from the tank to the reacting area, probably by means of gravity. Some sort of computer-controlled valve would control the flow rate of each of the supply lines. The reactants would flow into the reacting chamber, where they would come into contact and release heat. (Note that a safe yet powerful reaction needs to be found.) If the reaction vaporizes some of the reactants, than those gases could be used to drive the turbine. If that is not possible, than water could be used to transfer the energy, as in a standard steam cycle. Piping from the reacting chamber to the turbine and from the turbine to the exhaust area would be necessary. If all goes well, then the turbine would turn. The computer would monitor the speed of the turbine and adjust the flow of reactants accordingly. The rotating axle could be used to drive a fan, perhaps. Possibly, a dynamo could be attached, would could be used to light a light bulb.

Additional equipment would be necessary for this project. Two vats and a length of pipe would definitely be required. The size and material of the reacting chamber would be determined by the amount of heat the reaction would put out. Additional parts for the turbine, such as the blades, would be necessary. The dynamo is optional. For educational purposes, it would be best if the vats, pipes, and reacting chamber would be transparent. Plastic is cheaper and easier to handle; glass is stronger.

Some thermodynamics, controls, and chemistry would be taught through this lab. Its main advantage is that the concept is interesting and involves the skills of all of the project designers. Its main drawback include the possibility of messiness and the cost of procuring additional parts.

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