Study On Structure And Performance Optimization Of Gas Turbine Flowmeter

Gas turbine flowmeter is a traditional speed flow meter.It is widely used in the field of natural gas because of its outstanding advantages in gas flow measurement.In view of the current situation of increasing shortage of natural gas resources and instrument accuracy to be improved,the research on gas turbine flowmeter is very important to improve the national economy,reduce energy consumption and improve the performance of flow instruments.In this paper,combined with the methods of theoretical analysis,numerical simulation and experimental test,in order to reduce the pressure loss,reduce the linearity error and improve the accuracy,a structural optimization scheme to improve the metering performance of the TRZ80 gas turbine flowmeter is proposed.Firstly,the flow information in the original model is obtained by numerical calculation with FLUENT software.After flow field analysis,it is found that the pressure and velocity distribution of the front rectifier are uneven and the change gradient is large;Large negative pressure is generated at the rear end of the impeller;The turbulent distribution of the flow field at the tail of the rear guide fluid,the backflow phenomenon caused by fluid interaction and the vortex structure are the main reasons for the instability of the instrument and the measurement error.Secondly,based on the flow mechanism,the structure is optimized,and the simulated flow field information before and after optimization is compared and analyzed.Finally,the pressure loss,instrument coefficient and indication error are calibrated by the gas flow standard device to verify the feasibility of the optimization scheme.The results show that the helix angle of the impeller is the key factor affecting the performance of the instrument.When the helix angle is 45°～50°,it has better metering performance;Compared with the traditional semi-circular flow field,the optimized leading fluid has a more uniform distribution,and the linearity error is reduced by about 18.92%;The optimized rear guide fluid can greatly reduce the pressure loss,weaken the phenomenon of reflux and vortex,and the gas can flow out stably,so as to improve the stability of the instrument.The pressure loss and linearity error are reduced by about 43.03% and 27.03% respectively;After the combination of the two optimized structures,the pressure loss and linearity error are reduced by about 48.58%and 32.43% respectively;The three optimization schemes reduce the indication error and improve the measurement accuracy.