Design Of Power Turbine And Research Of Power Unit For Ship Waste Heat Recovery

The energy problem has become a top priority issue in economic development.Harbin Engineering University has designed a waste heat utilization system based on the 6S50ME-C8.2 diesel engine model.The system consists of a power turbine,a low temperature exhaust heat recovery boiler,a steam condensing steam turbine,Rankine cycle power generation systems and modules alternators and feedwater preheating systems.Turbine has been one of the most important components of waste heat utilization system using the energy stored in the working fluid to promote their work,to achieve the purpose of energy conversion.Turbine design as the main work of waste heat system components,this paper completed the following major tasks:(1)According to the requirements of main engine waste heat recovery system and given design parameters to complete the turbine design.Engineering design includes turbine structure selection,thermal calculation.The types of turbine structure are given respectively.Three kinds of schemes of two-stage and single-stage radial turbines and single-stage axial turbines are selected,and the single-stage radial flow thermal scheme is finally selected.According to the strict requirements of turbine heat and exhaust temperature,three kinds of thermal calculation schemes are designed for radial turbines.Finally,the second thermal calculation scheme is selected and the basic structural parameters of the turbine are obtained.(2)According to the turbine basic parameters calculated by the thermal calculation,the software of Concept NREC is used to design the vanes of turbine nozzle and rotor,and the ideal turbine structure is obtained by continuously adjusting parameters such as meanline(camber line),blade angle and blade thickness form.In this paper.The numerical simulation software Numeca also was introduced.The fluid control equations,turbulence models and numerical simulation methods are introduced respectively.The whole turbine is meshed by IGG / Autogrid5,and the numerical simulation of turbine flow field is given.In this paper,numerical simulation of turbine performance is also carried out,and the characteristic curves of the turbine under different rotational speeds are obtained.(3)In this paper,the performance of radial turbine is also studied.The influence of turbine tip clearance and numbers of blade on the performance of the turbine are studied.Using the control variable method to study different turbine efficiency,mass flow,blade Mach number map and so on were calculated and studied separately,from the turbine flow field for tip clearance and blade consistency on the turbine performance profound analysis,the turbine Design is instructive.(4)At the end of this paper,the research on the characteristics of turbine power generation unit is completed.The turbine high-speed shaft adopts the tilting pad bearing,the low-speed shaft adopts two-lobe elliptical bearing,and the finite element simulation of Dyrobes software is used to obtain high and low speed shaft bearings Design speed characteristics of the parameters.In order to effectively avoid the vibration caused by the approaching critical speed during the operation of the rotor,the critical speed of the rotor system and its rotor dynamics are also analyzed,and the critical speed and its dynamic characteristics of high speed shaft and low speed shaft are obtained.