Heat Transfer Conjugate Calculation Of Cooled Turbine And Cooling Structure Design Optimization

The cooling structure design optimization of a modified micro-small gas turbine was discussed in this paper.To improve the efficiency and output power of modern gas turbine,the turbine inlet temperature was greatly increased,but it also brought the normal operation of the gas turbine with a series of serious problems.The rising rate of turbine inlet temperature was much faster than the development of the blade material heat resistance performance,so effective cooling technology and thermal protection measures must be taken to ensure that the turbine blades can work safely and reliably under the high temperature environment.Compared with other types of gas turbines,micro-small gas turbine has high reliability,long service life,small installed capacity and flexible system.But at the same time the structure of micro-small gas turbine is more complex and the circulation area is small,which leads to a relatively small radial height of the turbine blade and more difficulties for turbine blade to use a complex cooling structure.Therefore,it is strongly necessary to deeply study the typical cooling structure in term of its characteristics of heat and gas flow,optimize and improve its cooling structure,which will lay a solid technical foundation for further improvement of its performance.The research object of this article is a 1MW micro-small high-pressure gas turbine.Because of the improvement of gas turbine power and the increasing temperature,the cooling structure of the stator was redesigned.Heat transfer conjugate(HTC)calculation methodology was used to simulate the redesigned high-pressure turbine.On the basis of this,the cooling structure was optimized,including the internal cooling and the film cooling,especially the use of the sister hole.At last,the influence of transition section on clocking effects of hot spot and cooled stators was studied.The research includes following contents:1.The HTC calculation of the uncooled high-pressure turbine before and after modification:The Mark ? was calculated to verify the reliability of the numerical simulation method.2.The design of the internal cooling structure and HTC calculation of the high-pressure turbine after retrofitting:The cooling structure of high-pressure turbine after retrofitting was redesigned according to original cooling structure.And the adaptability of original cooling structure after retrofitting was evaluated and the optimal design of fin and impingement holes was also taken.3.The film cooling structure optimization of high-pressure turbine after retrofitting:According to the second part,the composite cooling scheme with internal cooling and sister hole film cooling was adopted to further improve the cooling efficiency.The cooling effect of sister pore structure on the turbine was analyzed compared with ordinary gas film hole.4.The analysis of the clocking effects of hot spot and cooled stators:By combining inlet nonuniformities of high-pressure turbine(caused by uneven exports of reflux combustion chamber and C-type transition section),the influence of C-type transition on the clocking effects of hot spot and air-cooled turbine was studied and compared with axial flow transition section.