Date of Graduation

1997

Document Type

Dissertation/Thesis

Abstract

The comparison of two design variations of the Axial Vane Rotary Engine (AVRE) was done by evaluating several parameters. These two designs are called the Pin Cam and the Inverted Pin Cam designs. The first step involved developing a technique to determine the heat loads on the components of the engines since the engine is running at a steady state loading condition. The second step used this thermal data to get a final temperature profile. The third step combined the thermal data and the combustion data to perform a structural analysis of the engine components. This illustrated both the stresses and the deformations on the components. Finally in the fourth step, the knowledge that was gained is used to compare the Rand Cam{dollar}\\rm\\sp{lcub}TM{rcub}{dollar} with other engines. This was done with engines of the same displacement to determine what applications would be best suited for the AVRE. The pin cam and the inverted pin cam are basically modified versions of the beta version of the AVRE. As part of this thermal analysis an iterative process was done between a combustion model and a finite element analysis, of the thermal conduction to refine the definition of the combustion wall temperature as a function of shaft angle. This was done because the traditional approach for engines of a constant value for wall temperature was not appropriate for a rotary engine since the gases move along a wall that is at significantly different temperatures. As a result of this updated Twall ({dollar}\heta),{dollar} the thermodynamic parameters predicted by the combustion model increased by between five and fourteen percent. The results of the final thermal finite element analysis also showed that the peak surface temperatures of the engine components in both engines were reduced by about 40{dollar}\\sp\\circ{dollar}F. Finally, it was also shown that the initial prototypes that were analyzed are not thermally optimized. This is based on a simple change of materials that reduced the peak temperatures in the Pin Cam{dollar}\\rm\\sp{lcub}TM{rcub}{dollar} housing assembly by almost 200{dollar}\\sp\\circ{dollar}F. The stress analysis illustrated that for design purposes each component of the engine has a load that results in a stress value an order of magnitude higher than what any of the other loads creates. The vanes in both engines are controlled by the acceleration load case that causes a contact stress to develop at the pin and the tips of the vane. The other components in both engines are controlled by the thermal stresses. Thermal distortion is major factor in defining the clearances under operating conditions. In addition, an alternative vane design was looked at that uses a slot in the vane that rides on a rail. This resulted in reduced stress and loads on the vane during the controlling acceleration load case. Based on the results of this research it was determined that the pin cam design of the AVRE as modified with the alternative slotted vane would be the best choice to proceed with a thermal optimization. In fact a honeycomb structure was shown to be very effective at removing the high heat loads on the cam surface of the pin cam design. These optimizations are needed to develop a long lasting engine design of the AVRE.

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