Creation of object-oriented model of centrifugal pump on the basis of electro-hydrodynamic analogy method

Abstract

creATioN of objecT-orieNTeD moDel of ceNTrifuGAl PumP oN The bASiS of elecTrohyDroDyNAmic ANAloGy meThoD Purpose. Development of an objectoriented model of a centrifugal pump (CP), which would reflect the constructive features of the structure and processes in it, as well as the simultaneous balance of effort (delivery head and pressure), and flow (flow rates) variables, namely the balance of powers. methodology. Applying of the electrohydrodynamic analogy method to the flow diagram of liquid in a centrifugal pump en abled to synthesize the expanded complex equivalent circuit of a CP, spatially combined with its constructive elements. findings. The theoretical calculation of the CP performance characteristics according to its directory data for the entire interval of change in the flow rate duty taking into account the physical properties of the working fluid was carried out. Good agreement between the calculated and experimental performance characteristics of the main pump НM3600230 is illustrated. The relative error of calculations does not exceed 5-8 %. originality. The developed objectoriented model of the CP takes into account the vortical circulation processes of the motion of the liquid both at the input and output of the rotor wheel (impeller), and in the interblade space. Also, the model adequately reflects the link between the mechanical and hydraulic subsystem of the pump unit at all load modes, and especially in lowload ones, of its flow duty, taking into account its design parameters and physical properties of the working fluid. Practical value. The objectoriented model of the CP is easily adapted to modern computeroriented interactive tools (20sim, Simulink, Pspice, Dymola, etc.) designed to simulate the modes of operation of mechatronic technical systems, which in turn reveals the way for calculation and optimization of the CP power characteristics as an element of a pumping station.

Dynamic Modelling of Centrifugal Hydraulic Load of Pumping Station Electric Drive

“…To solve the set tasks, we will base on the CP mathematical model presented in [16]. This model makes it possible to study the steady state modes both of CP as a whole and of the main elements of its internal structure in sufficient detail, taking into account the effect of the rotational speed of the impeller, as well as of the density and kinematic viscosity of the working fluid.…”

“…The last parameter allows considering the influence of the working fluid temperature on the parameters of the CP elements and pumping modes, since the change in temperature of the fluid by tens of degrees can lead to a change in the kinematic fluid viscosity by orders of magnitude more. An important distinctive feature of the model presented in [16] from the previous solutions offered by the same authors is that the dissipative mechanical losses in the bearings, gaskets and disk friction of the CP fluid are presented by the non-linear active resistance dependent on the structural parameters of CP and the hydraulic coordinates of its mode.…”

“…Applying the mesh-current method, we will form the equation of the CP mathematical model based on its complex equivalent circuit presented in [16]. To do this, we transform the said circuit into a form suitable for writing the equations: In the steady state modes, the equations of the CP mathematical model (Fig.…”

“…where ω r and ω r.nom are the actual and nominal value of the rotation frequency of the CP impeller, respectively; It should be noted that the equation of the CP model, except for the equation 6describing the pipeline, is formed in the rotary system of d-q coordinates, rigidly connected with the CP impellers [16]. In this coordinate system, the internal parameters of CP do not depend on the impeller rotation angle, and the pressure heads and flow rates are its harmonic (approximately sinusoidal) functions.…”

“…In [16], the authors, being the closest to solving the research problem raised in this study, presented a refined CP mathematical model built by applying the principle of electrohydraulic analogy to combine models of its main structural elements. This model makes it possible to obtain the operational characteristics of the CP with a sufficient accuracy, taking into account the impact on them of the rotational speed of the impeller, as well as of the main physical parameters of the working fluid.…”