| Boiler feed water pump is a key component of the thermal power unit water system.It will have a certain temperature in the deaerator and water storage tank,and will be delivered to the boiler after the water supply is increased and the pressure is increased.The boiler provides stable water supply pressure and flow to meet the boiler water demand..The rapid development of super(super)critical thermal power units above 350 MW puts higher requirements on the safety,stability and efficiency of boiler feed water pumps.Once the boiler feed pump fails during operation,it will cause the unit to stop and cause significant economic losses to the power plant.According to the research and development requirements of a boiler and water pump,the main components of the hydraulic components such as the impeller and the guide vane,and the axial force balance mechanism are designed separately.After completing the hydraulic and structural design of the DG80-100 boiler feed pump,the external characteristics of the pump are predicted by numerical simulation,and the accuracy of the external characteristic prediction is verified by experiments,so that the DG80-100 boiler can be simulated in the numerical simulation environment.Analyze and study some characteristics of the feed pump.The specific content of the paper is as follows:(1)According to the design parameters of the enterprise,the hydraulic components such as the impeller and the guide vane are designed according to the relatively reliable speed coefficient method,and the hydraulic design diagram of the impeller and the guide vane is drawn;referring to the typical axial force balance mechanism,the design conforms to the boiler The pump uses the required balance structure,and proposes the DG80-100 boiler feed pump structure plan and draws the assembly drawing.(2)According to the designed hydraulic model of DG80-100 boiler feed pump,the relevant software is used to carry out solid three-dimensional modeling of the fluid domains such as impeller,vane,inlet flow channel and outlet flow channel,and adopts the physical non-structural technology.The grid completes the mesh division of the fluid domain,predicts the hydraulic performance of the DG80-100 boiler feed pump,and verifies the correctness of the numerical simulation by using the test.Based on this,the pressure and velocity distribution of the flow field in the pump under different working conditions are analyzed.The law of change provides a reference for the improvement of boiler feed water pump performance.By calculating the internal flow characteristics of the pump,it can be seen that the hydraulic calculation model is in good agreement with the experimental results,indicating that the simulation calculation model can faithfully reflect the real working condition of the pump;through the internal flow analysis,the internal flow law of the pump is reasonable and hydraulic.Designed to meet the required design parameters.(3)Based on the results of flow field analysis in Chapter 3,in order to judge whether the structure and material of the rotor system designed by DG80-100 boiler feed water pump are reasonable,the fluid-solid-thermal coupling analysis of the pump rotor system is required..Firstly,the pump-rotor system is subjected to flow-thermal coupling analysis to obtain the internal temperature field of the high-temperature medium.The solid model of the rotor system is established,and the corresponding flow field analysis results are coupled to the surface of the solid model,and the medium temperature factor is added.From the results,it is known that the internal temperature distribution of the pump rotor system is reasonable and the temperature difference is small;secondly,the rotor is The system performs flow-solid-thermal coupling analysis,and the internal flow field and temperature field of the pump rotor system calculated above are loaded into the solid structure to obtain the stress and strain of the temperature field and the flow field on the rotor solid structure.The designed rotor system has a reasonable structure and is selected correctly.(4)The DG80-100 boiler feed water pump rotor system is taken as the research object.The rotor dynamic characteristics of the pump are analyzed without prestressing and prestressing.The critical speed of the pump rotor is calculated by WORKBENCH software.The result shows that the rotor is excited.The vibration frequency is able to avoid the natural frequency of the resonance. |
