| Thermal power generation is one of the main power generation methods in China.The condensate pump is the key equipment in the power plant,its configuration can affect the safety and stability of the entire unit operation directly.The selection of the number and capacity of condensate pump depends on the role of the unit in the grid,equipment investment,equipment quality,unit capacity and many other factors.Centrifugal pump is high head and efficiency and the structure becomes more complicated due to its added impellers,and instability of flow field generated by the rotating impeller may lead to fatigue failure in the entire system.In this paper,the design,manufacture and test of the condensate pump for the4×360 critical are studied.This scheme is equipped with standby equipment,and when one of them fails,the standby can meet the needs of the unit,and the availability of the unit will not be affected.The primary work and conclusions are as follows:1.The existing water pump’s use of the system was collected and analyzed to combine with the main characteristic of the field test and to determine suitable development plan for pump system.The first stage of the condensate pump uses a double-suction impeller with a screw-type pump body,and the second stage uses a single-suction centrifugal impeller with space guide vanes.The whole pump adopts a core-pulling vertical structure.After the main body of the pump is installed in the outer cylinder,it is a closed vacuum design.It has small hydraulic loss,strong resistance to thermal shock and simple structure.2.The performance calculation of the established hydraulic model is carried out by the traditional hydraulic design method,including the determination of the similar working conditions,the calculation magnification factor,the determination of the performance conversion relationship,etc.3.The overall structure design of the pump and the functional characteristics of each component are described.The head adopts double suction impeller with spiral pump body and inducer structure design,the impeller material is made of cast stainless steel,this design scheme improves the anti-cavitation performance of the pump.4.The axial force of the pump is calculated,and the design and strength analysis of the entire rotor system of the condensate pump are carried out,including the strength check of the shaft,the calculation and verification of the axial force on the rotor system,and the critical speed of the rotor system Calculation,calculation and verification of the thickness of the impeller blades,and calculation and verification of other key components such as bearings and key couplings.The results meet the requirements of the agreement.5.The internal flow field of the pump was analyzed by CFD simulation,including the absolute velocity distribution,pressure distribution and turbulent kinetic energy of the primary and secondary impellers.The flow characteristics of the multi-stage pump are preliminarily analyzed.For the first-stage impeller and the pump body fluid domain,there is a jet-wake structure at the impeller outlet,especially when it deviates from the design conditions.The absolute velocity distribution of each flow channel of the impeller shows obvious asymmetry,especially under the condition of large flow.Aiming at the secondary impeller and guide vane fluid domains,under small flow conditions,the range of the outflow and vortex area in the impeller flow channel is large,and the flow velocity and pressure distribution in each flow channel of the secondary impeller show obvious symmetry.6.The test bed and circuit system of the pump are designed.The cavitation test and hydraulic performance test were carried out,through data recording and analysis,and the disintegration examination after the test,the reliability of the condensate pump running under the design conditions and the effectiveness of the pump design method and the feasibility of the manufacturing method are verified. |
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