| With the rapid development of deep-sea oil and gas extraction, storage and transportation of natural gas and other energy fields, the application of domestic PCL803centrifugal compressors in West-East natural gas transmission and other major natural gas pipeline projects becomes more and more widely. Pressure ratio, changing efficiency are important indicators of the changing centrifugal compressor performance. How to use numerical simulation methods to determine influence of impeller structural parameters on compressor pressure ratio, changing efficiency and internal flow field is the urgent problem of centrifugal compressor design to solve. Based on computational fluid dynamics method, internal flow field of the e impeller of PCL803centrifugal compressor in a station on the West-East natural gas transmission was numerical simulated. The whole paper mainly carried out the following aspects:(1) Application of the domestic centrifugal compressors for West-East natural gas transmission project was statistical analyzed. The structure parameter data, design information, operating conditions, etc. of PCL803centrifugal compressor were collected;(2) In connection with structural features of PCL803compressor impeller, the basic equations of impeller flow was established and Reynolds averaging method standard k-ε model was selected as turbulence model t. Standard wall function was chosen to compute the near-wall region. MRF model was used to process stationary and rotating impeller region while using second-order upwind to control equation discrete and SIMPLEC algorithm to solve discrete equations;(3) Based on data collected, three-dimensional models of the first stage impeller were established by using Pro/Engineer software. Grids were meshed by unstructured tetrahedral. Boundary and initial conditions were reasonable set. Impeller iterative solution was carried out by FLUENT. By comparison of the calculated results and experimental data, the calculation method chosen is reliable. And the numerical model is appropriate to analyze centrifugal compressor impeller flow field and aerodynamic performance;(4) Using the same calculation method, the number of impeller blades, blade thickness, blade mounting outlet angle were changed.15groups of impeller models were established. The internal flow field of impellers was numerical simulated, changing the impeller inlet mass flow within the scope of1.57kg/s-6.57kg/s, the effect of structural parameters of impeller on PCL803compressor pressure ratio, changing efficiency were analyzed;(5) Based on the above study, preferred proposal of the impeller was put forward. The number of blades of initial impeller was15, the blade thickness was12mm, and the outlet installation angle of the blade was77.5°. The number of blades of preferred impeller was16, the blade thickness was14mm, and the outlet installation angle of the blade was82.5°.The results showed that:The internal flow condition can be improved by increasing the number of blades of impeller. When the number exceeds a certain upper limit of the blade, total pressure ratio was increased slightly due to the increase of the sliding coefficient while the efficiency was reduced because of increases of the blades surface friction loss. The pressure ratio was reduced while the impeller efficiency was increased with leaf thickness increases. But the percentage increased in efficiency was greater than that of reduced in pressure ratio. As the exit angle increased, static pressure ratio and efficiency of the impeller gradually increased. However, polytrophic efficiency would not increase and enhance of the compression ratio is small when the blade exit installation angle reached82.5°.The average pressure ratio was improved by1.82%and there was an increase of3.81%in polytrophic efficiency. We can save3,357,000yuan of electricity by using preferred impeller.
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