Browsing by Subject "Direct energy conversion"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Optimization of AMTEC-TIEC cascade and analysis of the algorithm used for solving the non-linear system of equations in the thermal model(Texas Tech University, 1999-12) Mustafa, AhmedA mathematical modeling of a system consisting of Thermionic Energy Converter (TIEC) and an Alkali Metal Thermal to Electrical Converter (AMTEC) is performed to optimize the efficiency of the cascade. The TIEC is heated by electron bombardment, which converts heat partially into electrichy and rejects the remaining. The AMTEC utilizes the rejected heat. A thermal model of the cascade converter has been developed to analyze the key parameters such as power level, heat fluxes, and temperatures. The efficiency of the cascaded cell is improved and h is greater than any of the individual efficiencies of the cells and smaller than the sum of the individual efficiencies. The problem is divided into two smaller segments and then MATHCAD was used to solve 12 non-linear system of equations. Algorithms for solving the system of non-linear equations are also analyzed. The order of two of the algorithms are calculated and recommendation is made for a custom made program which can be used for solving the whole 16 node system of non linear equations.Item Optimization of the TIEC/AMTEC cascade cell(Texas Tech University, 1998-12) Malka, Vivek RaoA mathematical modeling of a system consisting of a cascade of a thermionic energy conversion (TIEC) device and an alkali metal thermal to electric converter (AMTEC) device has been performed to optimize the efficiency of the cell. The TIEC is heated by electron bombardment, which converts heat partially into electricity and rejects the remaining. The AMTEC utilizes this reject heat of the TIEC. Cascading these two cells provides lots of advantages. A mathematical model of the cascade converter has been developed to analyze the effects of key parameters such as power level, heat fluxes, and temperatures. In this effort, a 12-node system of nonlinear simultaneous equations has been constmcted which is solved by MATHCAD and a locally optimized efficiency has been derived. Thus, efficiency of the cascaded cell is improved, so that it is greater than the highest efficiency among the TIEC and AMTEC and lower than the sum of their individual efficiencies. The results were compared with the previous program written for the same problem.Item Power degradation and performance evaluation of BASE in AMTEC(Texas Tech University, 2000-05) Vijayaraghavan, PrasannaPower degradation in the PX-3 A Alkali Metal Thermal-to-Electric Converter cell refers to the problem of decrease in power output with time. This problem has been observed for 12000 hours of operation of the cell in experiments. Since the cell has applications in deep-space exploration, it is necessary that the power output does not fall to levels below the minimum requirements of the spacecraft. It is therefore important to investigate the reasons for this power loss. The cell uses â-alumina as a solid electrolyte. The material degrades with time as a result of the chemical and thermal conditions within the cell during operation, â- alumina degradation manifests itself as an increase in its ionic resistance which reduces power output. The â-alumina is responsible for almost all of the power degradation in the first 7000 hours of operation. Thereafter, though â-alumina degradation continues to cause power loss, other factors, components and materials in the cell also contribute to power loss. The role of the P"-alumina in power loss is investigated and quantitatively established and it is shown that other components also are responsible for power degradation. Finally, some suggestions are made that will help reduce the rate of power degradation and extend the useful and functional time of the cell.