Influences of Incidence Angle on 2D-Flow and Secondary Flow Structure in Ultra-Highly Loaded Turbine Cascade简

An increase of turbine blade loading can reduce the numbers of blade and stage of gas turbines. However, an in- crease of blade loading makes the secondary flow much stronger because of the steep pitch-wise pressure gradient in the cascade passage, and consequently deteriorates the turbine efficiency. In this study, the computations were performed for the flow in an ultra-highly loaded turbine cascade with high turning angle in order to clarify the ef- fects of the incidence angle on the two dimensional flow and the secondary flow in the cascade passage, which cause the profile loss and the secondary loss, respectively. The computed results showed good agreement with the experimental surface oil flow visualizations and the blade surface static pressure at mid-span of the blade. The profile loss was strongly increased by the increase of incidence angle especially in the positive range. Moreover, the positive incidences not only strengthened the horseshoe vortex and the passage vortex but also induced a new vortex on the end-wall. Moreover, the newly formed vortex influenced the formation of the pressure side leg of horseshoe vortex.     

Performance analysis of a novel solar PTC integrated system for multi-generation with hydrogen production

The performance analysis of a novel multi-generation (MG) system that is developed for electricity, cooling, hot water and hydrogen production is presented in this study. MG systems in literature are predominantly built on a gas cycle, integrated with other thermodynamic cycles. The aim of this study is to achieve better thermodynamic (energy and exergy) performance using a MG system (without a gas cycle) that produces hydrogen. A proton exchange membrane (PEM) utilizes some of the electricity generated by the MG system to produce hydrogen. Two Rankine cycles with regeneration and reheat principles are used in the MG configuration. Double effect and single effect absorption cycles are also used to produce cooling. The electricity, hot water, cooling effect, and hydrogen production from the multi-generation are 1027 kW, 188.5 kW, 11.23 kg/s and 0.9785 kg/h respectively. An overall energy and exergy efficiency of 71.6% and 24.5% respectively is achieved considering the solar parabolic trough collector (PTC) input and this can increase to 93.3% and 31.9% if the input source is 100% efficient. The greenhouse gas emission reduction of this MG system is also analyzed.