Purpose The gaps between runner and nearby structures play an important role in the dynamic response of runner, especially for pump-turbines. This paper aims to evaluate gap influence on added mass stress pump-turbine provide improved method predict resonance runner. Design/methodology/approach Acoustic-structural coupling was used factors a reduced scale with different axial radial size rigid walls. Improved one-way fluid-structural interaction (FSI) simulation calculate which takes into...

After long-term operation, the material loss due to slurry erosion often leads significant changes in impeller geometry. This change can, turn, affect flow characteristics and mechanism a centrifugal pump. To investigate this matter, we consider two geometric models based on prototype stainless steel impeller, which failed huge problems from pulp slurry. These are different degree of wear, with one model at pre-erosion stage other worn blades. For both models, have been obtained Eulerian...

The startup process occurs frequently for pumped storage units. During this process, the rotating rate that changes rapidly and unsteady flow in runner cause complex dynamic response of runner, sometimes even resonance. sharp rise stress large-amplitude stresses will greatly shorten fatigue life. Thus, study start-up turbine mode is critical to safety operation. This paper introduced a method coupling one dimensional (1D) pipeline calculation three-dimensional computational dynamics (3D CFD)...

The free-surface vortex is simulated with the homogeneous mixture approach. In order to define suitable boundary conditions in two-phase flow field, a numerical strategy proposed on air mass conservation recirculating system. approach verified from an experiment. Numerical results agreed well experiment not only circulation but also axial velocity gradient. On assumption, compressibility corrections for turbulence modelling had almost no effect result this case study. estimate continuous...

Purpose The purpose of this paper is to reveal the transient thermo-elasto-hydrodynamic lubrication mechanism a bidirectional thrust bearing in pumped-storage unit, and propose simulation method two-way fluid-solid-thermal interaction bearing. Design/methodology/approach used simulate three-dimensional bearing, during start-up shutdown process pumped storage unit. A pad including an oil hole modelled analyze temporal variation characteristics, such as film pressure, thickness temperature,...

The S-shaped characteristic curves in pump-turbines complicate synchronization with the electrical grid and affect system safety. Misaligned guide vanes (MGVs) are one of most effective solutions to avoid characteristics. internal flow mechanism MGV for improving characteristics was studied by numerical analysis. Six operating conditions were modeled region. Four arranged as MGVs qualitatively quantitatively analyze behavior. quite complex at four points without MGV; here, attack angle...

For the low-head hydropower station, operating head is low, and turbine intake channel relatively short. The internal flow behaviour can be influenced by fluid flows in upstream reservoir easily, then it would influence hydraulic performance. Water Coriolis force Earth rotation, differs at different Rossby number. In this paper, effect on approach performances are investigated numerically for units. Firstly, (under latitudes same characteristic length scale) was predicted. Secondly,...

Based on the SST liquid turbulence model, using Euler-Lagrange method to simulate solid-liquid two-phase flow in centrifugal pump with different degree of wear blades. When was transporting silt-laden flow, numerical simulations analyse trajectory sands and mechanism wear. According simulation results, when rate is less than design efficiency decreases gradually increase runner blade. larger designed rate, will decrease first then increase. As increases, head power are increasing. With...

Abstract Hydro-abrasive erosion due to sediment flow often leads the efficiency loss, seriously vibration, and sometimes even failure for Pelton turbines. This kind of can be greatly intensified when concentration sand increases. It is paramount importance study mechanism such machines, especially in Asia, where many rivers relatively higher some geologically young mountains like Himalayas. In this study, patterns injector have been predicted at high concentration. The simulated scenario was...

At present it is possible to predict more accurately by various numerical methods established for cavitation simulation around a hydrofoil. However, the solution of complex unsteady cavity flow, still marginal. In this paper, method adopted simulate 3-D NACA0015 hydrofoil with homogeneous two-phase flow calculation using commercial code CFX-solver two turbulence models, standard RNG k- model and modified respectively. First, pressure coefficient non-cavitating time averaged values are...

Since the clearance between runner shroud and hub can change with angle of blades, it has a great influence on hydraulic characteristics cavitation performance in Kaplan Turbine. In this paper, CFD will be used to solve turbulence model based k-ωSST entire flow field turbine Zwart-Gerber-Belamri predict cavitation. We compare Turbine under conditions exist or absence. Finally, we analysis width relationship clearances characteristics.

Abstract From the perspective of world hydropower utilization trend, medium and high head hydraulic resources are gradually decreasing, along with much more attention to ecological environment land resource constraints, low-head plants have been becoming particularly prevalent. Benefit from compact structure, less investment, capacity wide operation range, bulb tubular turbines come up be optimal option for development exploitation energy widely applied. In this paper, based on measurement...

With the strong demands on further development of economy and energy, tidal with own green renewable advantages, has gained more attention, which as main application type, bulb tubular turbines have played an important role in power exploitation. Characteristic low head large discharge, flow properties a turbine turn out to be complicated, seriously affects actual operation performance station. To promote wide it is ritual deeply dig into turbine. In this paper, bulb-type model used for...

With the development of offshore oilfields, foreign companies and research institutes spend plenty resources on subsea multiphase pump. The helico-axial pump is generally characterized by large flow high head unit, has advantages good anti-sand performance, simple structure small volume. This paper introduces design two-stage compression unit model a using CFD method. A numerical simulation full three-dimensional field carried out to study blade number wrap angle influence external...

Abstract The operating condition of dredge pump is highly complicated, a technical issue the shaft vibration problems, which has great effects on operation safety and stability pumps. This paper introduces mathematical model rotor dynamics for pump, used to numerically investigate critical speeds mode shapes under different bearing stiffness damping. damping shafting characteristics are considered. results show that effect 1 st 3 rd order speed can be ignored. little axial torsional natural...

Abstract The bidirectional thrust bearings are used to balance the load of entire shaft system which play an important role in pumped storage units. lubrication is usually analyzed by simultaneously solving Reynolds equation, energy film thickness equation and heat conduction elastic equilibrium pad. However, this method assumptions for inlet temperature wall coefficients on pad greatly affect numerical accuracy. This study fluid-solid-thermal interaction method, built three dimensional (3D)...