Effect of import bend and forward turbolator on performance of centrifugal pump

Abstract: As an important kind of fluid conveying equipment, a centrifugal pump is widely used in modern industrial production, but the issue of its low operation efficiency was not solved effectively, and at the same time a large amount of energy is consumed by a centrifugal pump every year, a huge burden has been brought on economic development. In order to improve the operation performance of a centrifugal pump, with the idea of improving the inlet flow field of a centrifugal pump, three kinds of bend forward turbolators were designed. First of all, the blade and central body of the turbolator and the centrifugal pump were modeled by Pro/E, and then meshed in Gambit. Finally, the whole flow field of a centrifugal pump with an imported bend was simulated under the design conditions by using a MRF model which was supported by Fluent, both the standard k-ε turbulence model and the SIMPLE method were adopted to solve the Navier-Stokes equations for incompressible flow. According to the simulation results under different import lines, it was concluded that both the turning radius (R) of the 90 degree elbow and entrance straight tube length (L) of the bend had an influence on operation efficiency, and that the former was more obvious. The efficiency of a centrifugal pump can be effectively improved by increasing R, and it will be first increased and then decreased with the increasing L, the maximum efficiency can be reached when L=D, so the operation efficiency can be improved by an appropriate increase of R and L, the maximal efficiency can be up to 81.98%. After installing a turbolator, the inlet flow state of a pump got a considerable improvement, the efficiency of centrifugal pump was improved, and from all kinds of turbolator, the CJ-3406 had the most obvious effect, it can increase the efficiency by 4%. This indicates that the efficiency can be better improved when the aerofoil curve changes gently. With a turbolator, the work space of a centrifugal pump can be saved, so the turbolator can be better served for actual production. At the same time, the speed direction is perpendicular to the impeller inlet when the fluid flow through the pipe elbow. Centrifugal pump inlet flow can be more uniform and axisymmetric flow can be involved in the import which ensures the uniform distribution of pump inlet pressure. What is more, both the pressure and velocity of the import are improved, so the performance of anti-cavitation of a centrifugal pump is enhanced, the NPSHa can be increased by 0.2 m with the turbolator of 3307b. This article provides a new train of thought for improving the inlet line and the operation performance of a centrifugal pump in actual production.