Guide Vane Research Articles

Design and Manufacture of SiC/SiC Nozzle Guide Vanes With Environmental Barrier Coatings for High-Pressure Turbines

Abstract Increasing the efficiency of jet engines is essential to meet the demanded climate targets. Ceramic matrix composites (CMCs) are strong candidates for aircraft applications because they withstand high temperatures, while their density is two-thirds lower than that of conventional nickel-based alloys. This leads to cooling air savings and a lower overall engine weight, resulting in a potential reduction of emissions. To investigate the potential benefits and manufacturing techniques required for the introduction of CMC to the high-pressure turbine (HPT) of a modern jet engine, the geometry of a nozzle guide vane of an existing turbine was redesigned considering ceramic specific constraints. Then, the liquid silicon infiltration (LSI) process was used to manufacture silicon carbide fiber-reinforced silicon carbide (SiC/SiC) nozzle guide vanes (NGV). Hi-Nicalon S woven fabric was used together with a chemical vapor infiltration (CVI)-based fiber coating. The outer surface of the vane was ground to meet the requirements for surface roughness, and geometric and positional tolerances. Cylindrical, laser-drilled cooling holes were introduced for trailing edge cooling. In the final step, an environmental barrier coating (EBC) system consisting of yttrium disilicate (Y-DS) and yttrium monosilicate (Y-MS) layers was applied using physical vapor deposition (PVD) processing. Wind tunnel testing under technology readiness level (TRL) 4 will be performed and vane performance will be evaluated.

Phase classification and transient effects of the start-up process of multi-functional pump station in pump mode

In the context of achieving the goal of carbon neutrality, multi-functional pump stations (MFPS) have been greatly developed as a new energy system in recent years. The MFPS can operate in forward direction in pump mode to pump water and in turbine mode in reverse direction to generate electricity. At present, the instability of the MFPS during start-up process (SUP) in pump mode has become the key to restricting the operating life and further development of MFPS. In this paper, based on the motion characteristics of the pump and the cut-off facility (COF), the SUP of the MFPS in pump mode is clearly classified. In order to reveal the transient effect during the SUP, the steady-state full characteristic experiment (SFCE) of the pump was carried out. The occurrence phase of the transient effect during the SUP is analyzed, and the deviation between the steady-state external characteristics and the transient characteristics is revealed. In this study, the evaluation formula of the start-up completion degree (SUCD) of the MFPS in pump mode is proposed for the first time, and the evaluation and identification of the start-up progress at different phases are completed. The results show that the water flow in the system is in a reverse flow state in the Phase I. The SUCD of Phase I is 17 %. In the Phase II, The high-speed jet flow in the pump flows to the inlet of the guide vane (GV), which gradually changes the mainstream direction in the GV. A certain vortex structure can be observed at the exit of the flap gate (FG). The SUCD of Phase II is 61 %. In the Phase I and II, the dimensionless head of transient simulation is much larger than that of SFCE. In the Phase III, the flow state in the impeller will gradually stabilize. The transient effect disappears and the pressure fluctuation intensity decreases. The SUCD of Phase III is 93 %. In the Phase IV, the separation vortex that persists from Phase I-III at the tail of the GV blades disappears. The diversion capacity at the gate increases, and significant annular flow can be observed near the FG.

Numerical Investigation of Sediment Erosion in Guide Vanes of Francis Turbine with Experimental Validations

Abstract Serving as crucial elements within the distributor of Francis turbines, guide vanes aid in converting pressure energy into velocity energy. Additionally, they are responsible for directing water into the runner at the appropriate angle and quantity. The existence of a clearance gap in the guide vanes leads to the development of a leakage flow due to the pressure variation between the two sides. This leakage flow develops into a vortex, which interacts with sediment-laden flow and causes erosion of the guide vane as well as the runner. This study conducts a comprehensive analysis of erosion patterns in the guide vanes of a 2-kW model Francis turbine. Employing a dual approach that combines both experimental and computational methods, the investigation focuses on the impact of clearance gaps on erosion. The numerical study focuses on two cases, one incorporating a 2 mm clearance gap on the hub side of the guide vane and the other without the clearance gap. Both studies report erosion initiating from the mid-section and extending to the trailing edge at the suction side of the guide vane. Noteworthy is the leakage flow from the pressure side to the suction side of the blade, which, when converging with the main flow, disturbs the primary flow pattern and forms vortices, leading to erosion. This research also shows that the results from both the experimental and numerical analyses are in agreement.

Guide vane angle and reactor coolant pump performance during idling

In order to study the influence of different guide vane angle variation on performance characteristics of reactor coolant pump (RCP) during idling process, the external characteristics of RCP model with five different guide vane angles at idling process state were analyzed. Radial force characteristics and blade load characteristics of RCP were analyzed. The results show that the head and torque changes of pump with different guide vane angles in different idle period are consistent. The head of DY1model (Guide vane angle increases sharply first and then decreases gently, which convexity is large) is the highest and torque is small. The head drop rate of DY5 model (Guide vane decreases first and then increases, and the concavity is large) is the highest and torque is the largest. With the idling, the radial force of impeller and guide vane decreases gradually. The radial force of DY5 model impeller is small and the fluctuation range is weak. The radial force of DY4 model (Guide vane shows concavity change with gentle increase) impeller before idling is the largest. In the nonlinear transition of idle period, the total radial force of DY4 model is 235 N when idling for 32 s, which is nearly 30 times lower than that before idling, and the radial force decreases the most. In different idling periods, the radial force amplitude of guide vane of DY5 model is the largest, and the radial force decrease amplitude of guide vane of DY4 model is the largest in the whole idling period. The impeller blade load of DY4 and DY5 model pumps with concavity guide vane angle change law is significantly higher than that of other model pumps after the relative position of streamline is 0.6. When the relative position of the guide vane along the streamline direction is less than 0.5, the load fluctuation of the guide vane of each model pump is large. When the relative position is greater than 0.5, the blade load fluctuation is relatively small.

Estimating Wear Rate of Guide Vanes in High-Head Francis Turbines through Flow-Through Testing and DPM Simulation

Abstract The development of high-head water resources poses a significant concern due to hydro-abrasive erosion caused by entrained sediment particles. This issue is particularly prevalent in the muddy rivers of the Xinjiang region, China, where Francis turbines are commonly used. With increased soil erosion and rapid sediment transport, the erosion of Francis turbines, especially the guide vanes of high-head turbines, has become increasingly severe. The paper explores key factors that influence the erosion process caused by sediment-laden water. In addition to flow velocity and mud concentration, the properties of the sediment-laden water, such as hardness and size of sand particles, and the concentration ratio of sand particles with different hardness, also play a crucial role in the erosion process. The study is focused on analyzing the erosive effects of sediment-laden water on a high-head Francis turbine’s guide vane. The efficacy of the discrete phase model (DPM) as a simulation method for assessing wear on the guide vane is validated. This model helps analyze critical wear areas on the surface of the vane, enabling the identification of regions most severely affected by erosion due to sediment-laden water. By pinpointing these critical wear areas, the study provides valuable insights into the potential damage caused to the guide vane, thus contributing to better understanding and potential mitigation of erosion in similar turbine systems.

Experimental study of the effects on performance of Francis turbine due to sediments in flow

Abstract The sediments in the flow cause deterioration of components of the hydraulic machinery and influence fundamental properties such as density and viscosity of the flowing fluid. Earlier researchers have demonstrated the influence of sediment-laden flow on the performance of pumps, but such investigations have not been performed for the Francis turbine. This research focused on the effects of sediment-laden flow on the performance of a Francis turbine. Hydropower Research Centre for Himalayan Region (HRCHR) had a laboratory facility especially designed to conduct tests on Francis Turbines with sediments in the flow. The test rig was a closed-loop type and had provisions for mixing sediments with water and maintaining a uniform sediment concentration throughout the circuit. The performance of a 2 kW Francis turbine was tested at three different GV (Guide Vane) angles for different load conditions with and without sediment in the flow. The results showed that there was no change in maximum efficiency in the case of a smaller GV opening, whereas the maximum efficiency in the case of sediment water was reduced for a larger GV opening. Meanwhile, Sediment particles did not affect the head under the same discharge, whereas output power decreased slightly for sediment-laden conditions.

A comprehensive investigation on Darrieus vertical axis wind turbine performance and self-starting capability improvement by implementing a novel semi-directional airfoil guide vane and rotor solidity

Darrieus vertical axis wind turbine is classified as a lift-based power generation turbomachine. However, it is burdened with the limitations of mid-range efficiency and requiring initial torque for startup. The quest to improve the turbine's performance has focused on enhancing its aerodynamic performance and self-starting ability. One of the most effective approaches is to flow control and injection toward the rotor blades. This computational fluid dynamics research study utilizes a novel geometry known as the “Semi-Directional Airfoil Guide Vane” (SDAGV) to inject airflow smoothly and effectively toward the rotor blades at the upstream section. The investigation found that using a two-passage SDAGV increased rotor efficiency by up to 55% at a tip speed ratio (TSR) of 2.5. The pressure distribution analysis showed that azimuth angles between 90° and 135° significantly impacted the rotor's self-starting ability. Additionally, studying the turbine solidity revealed that a five-bladed rotor with SDAGV had a higher self-starting capability and efficiency than a two-bladed rotor with SDAGV. This was because its power coefficient (Cp) was approximately 160% greater at TSR = 1.4. Due to blade-to-blade interaction, high-solidity turbines from TSR = 2 onwards face performance challenges, which means their efficiency drops in the low-TSR range.

Design and Study of a Sediment Erosion Test Device for a Single-Flow Channel in the Guide Apparatus of a Reaction Hydraulic Turbine

Sediment erosion damage is one of the main causes of structural failure in reaction turbine units. To study the mechanism through which sediment erosion affects the water-guiding mechanism of a reaction turbine unit, this study obtained the average concentration and particle size of sediment during the flood season based on the statistics of the measured sediment data from the power station. Additionally, the characteristics of the solid–liquid two-phase flow of the diversion components of the reaction hydraulic turbine were numerically calculated. Based on the velocity triangle change in the guide apparatus and the flow similarity principle, a flow-around wear test device for the guide apparatus of the reaction turbine was designed. Furthermore, the similarity of the sand–water flow field between the guide apparatus of the prototype unit and the test device was compared and analyzed. The results demonstrated that the sand–water flow field of the diversion components of the prototype unit was axisymmetric and exhibited a potential flow distribution. Additionally, uniform sand–water flow occurred within the guide apparatus, with a small sand–water velocity gradient near the wall of the stay vanes (SV) and the guide vanes (GV). The maximum volume fraction of sediment particles was observed in the tailing area of the spiral casing, indicating an enrichment phenomenon of sediment particles. The velocity of the sediment particles on the surface of the guide vane in the single-channel sediment wear test device and prototype unit ranged from 6.2 to 7.8 m/s, and the velocity of the sediment particles on the surface of the stay vane ranged from 5.1 to 14.6 m/s, and the difference of the sediment particles’ velocity near the wall was 1 to 3 m/s. The trailing vorticity of the guide vane reached a maximum of 120 s−1. Consequently, the single-channel sediment erosion test device can unveil the sediment erosion mechanism of the guide apparatus of a reaction turbine.

Experimental Study on the Effect of Foil Guide Vane on the Performance of a Straight-Blade Vertical Axis Ocean Current Turbine

Indonesia is a country that has enormous energy potential for ocean currents, but the speed of ocean currents is relatively low. The straight-blade vertical axis ocean current turbines can be used to generate electricity. However, one of the disadvantages is lower performance compared to horizontal axis turbines. This study aims to improve the performance of straight-blade vertical axis ocean current turbines using a foil guide vane (FGV). Experimental studies have been conducted in a water tunnel at the Energy Systems Engineering Laboratory, Institut Teknologi Sumatera (ITERA), South Lampung, Indonesia. The investigation is carried out in two stages: the straight-blade without FGV as the original object; the straight-blade with FGV as a variation to improve the turbine performance. The investigation results show that the FGV can enhance the performance of straight-blade vertical axis ocean current turbines such as self-starting, torque coefficient (C_t), and power coefficient (C_p). The FGV has increased self-starting capability at a minimum current speed of 0.078 m/s by 15.3 rpm. The increase in maximum torque coefficient (C_t max) and power coefficient (C_p max) due to the FGV is 32% and 20%, respectively, with a C_t max of 0.829 and 〖a C〗_p max of 0.519. In addition, an investigation was also carried out on flow visualization. It showed that FGV could absorb a lot of injection ink, which means that the turbine with FGV absorbs more kinetic energy than without FGV.

Mitigation effect of guide vanes on the vortex-induced vibration of a long-span closed-box girder suspension bridge

This paper investigates the VIV responses and triggering mechanisms of a closed-box girder by wind tunnel experiments and computational fluid dynamics (CFD) simulations. The effects of handrails, gantry rails, and guide vanes (GVs) on the mitigation of VIV are analyzed. The results show that large-scale vortices shed from handrails and gantry rails result in large heaving VIV responses. The torsional VIV occurs due to the alternate vortex shedding in the wake. A handrail with a higher porosity near the upper deck surface is highly effective in suppressing VIV responses, especially for heaving VIV. Gantry rails installed at the medial position of the lower deck surface can mitigate torsional VIV to a large extent. GVs installed inside the gantry rails can mitigate torsional VIV much more significantly than one installed outside. For the girder with high-porosity handrails and GVs installed inside the gantry rails, the large-scale vortices generated by the handrails disappear, and the scale of the vortices induced by the GVs is notably reduced, thereby eliminating the heaving VIVs. Additionally, the vortex scale is reduced in the wake region, while the distance between the girder and vortex shedding increases. This effect significantly reduces torsional VIVs.

Efficiency Improvement and Market Value Analysis of Guide Vane Electrostatic Precipitators

Urbanization and industrialization accelerate, the issue of atmospheric environmental pollution has become increasingly severe, particularly the impact of indoor air quality on human health and well-being. This study introduces a novel guide vane electrostatic precipitator that significantly enhances dust removal efficiency through optimized airflow channels and electrostatic field design. Experimental data demonstrate that this device can effectively reduce PM2.5 concentrations, improving dust removal efficiency by approximately 10% compared to traditional electrostatic dust removal technologies. Applications in various scenarios, including hotels, dust workshops, and steel foundries, indicate that the device not only improves air quality, enhancing employee productivity and well-being, but also features low energy consumption and intelligent operation. Furthermore, it holds considerable potential market value, contributing to the promotion of green and low-carbon development objectives. This research provides a comprehensive analysis and evaluation of the structure, working principle, mechanism of efficiency improvement, practical application effects, and market value of the guide vane electrostatic precipitator, looking forward to its application prospects in the field of air purification.

Study on Wear Characteristics of a Guide Vane Centrifugal Pump Based on CFD–DEM

Guide vane submersible centrifugal pumps are a kind of submersible pump, and the fluid inside the pump is often mixed with gravel and other impurities during operation, affecting the pump’s operating efficiency and life expectancy. However, past studies on solid–liquid two-phase flow (STF) and wear characteristics in guided vane centrifugal pumps have been limited to the particle trajectory and wear region distribution. These studies have lacked research on the effect of particles on the fluid flow and the specific amount of wear on the overflow components. Additionally, most of them have used the DPM discrete-phase model, which does not consider the particle–particle and particle–wall interactions. This paper is based on the CFD–DEM method, combined with the Archard wear model. A solid–liquid two-phase flow simulation is carried out for pumps with different particle sizes and particle shapes to analyze the particle movement inside the pump, the wear distribution and average wear amount of the overflow components, and the effect of particles on the turbulent kinetic energy of the fluid. The results show that the particles mainly collide with the leading and trailing edges of the impeller blades and the leading edge of the guide vane blades and form a buildup at the trailing edge of the concave surface of the guide vane blades, resulting in the wear being mainly distributed in these regions. With an increase in particle size and a decrease in sphericity, the average wear on the overflow components increases. The change of particle size directly affects the resistance of the fluid and the structure of the flow field, which has a large impact on the fluid flow pattern and generates large turbulent kinetic energy fluctuations. The shape of the particles only changes the structure of the local flow field, which has a small impact on the fluid flow pattern.

Numerical Investigation of Guide Vane Hydraulic Torque Characteristics of a Pump Turbine in Pump Mode

This study performs numerical simulations to investigate the hydraulic torque characteristics of a pump turbine at different guide vane openings in pump mode. The SST k-ω turbulence model is utilized to simulate the flow field at guide vane angles from 1° to 21°. The simulation results reveal that the overall hydraulic torque shows a decreasing trend as guide vane opening increases. However, significant asymmetry of hydraulic torque exists among different guide vanes at certain openings. This asymmetry highly correlates with the large vibration observed during pump start-up in the field test. By analysing pressure contours and velocity streamlines at openings of 3°, 9° and 17°, the causes for torque asymmetry are explored in depth. The primary factors are identified as circumferential flow non-uniformity, distinct flow discharge tendencies between boundary guide vanes, and reverse flow towards upstream stay vanes. The research findings provide important insights into the hydraulic torque characteristics of pump turbines at off-design conditions, and offer valuable guidance for the optimal design and stable operation of pump turbines in pump mode.

Design Method for Impeller of Centrifugal Pump With Guide Vanes Based on Oseen Vortex

Abstract Centrifugal pumps with guide vanes (GVs) are widely used in a pump as turbine, energy storage pump station, and water diversion project. The objective of this study is to establish a design method of centrifugal pumps for matching impeller outlet and diffuser inlet to reduce hydraulic loss. To this end, a theoretical prediction model based on the fluid governing equation and the Oseen vortex model is proposed to predict the velocity moment downstream the impeller of the centrifugal pump. Then, a design method is established to design the impeller of the centrifugal pump with guide vanes. A centrifugal pump with a specific speed of 127 is used to validate the theoretical prediction model, and results of velocity moment show that the deviation between predicted and simulated results is below 0.5% in average. Finally, the design method is applied, and results show that the average efficiency of redesigned pump under the working conditions is 1.04% higher than that of baseline pump, which validates the reliability of proposed design method by theoretical prediction based on Oseen vortex. Analysis on velocity distribution and turbulence eddy dissipation shows that the design method based on Oseen vortex can effectively improve the flow pattern and pump performance.

Heat Transfer Coefficient and Adiabatic Effectiveness Measurements on a Nozzle Guide Vane With a Single Row of Cylindrical Holes

Abstract Film-cooling injection significantly affects the thermal behavior of turbine vane surfaces. In addition to the beneficial effect of the film shielding the vane from the hot gas flow, alteration of the thermal boundary layer should also be taken into account. The aim of the present work is to detail the film-cooling performance in terms of adiabatic effectiveness and external heat transfer coefficient on a 2D nozzle guide vane. A single row of cylindrical holes was tested on both pressure and suction sides of a literature vane, the VKI LS89, in a linear cascade. The employed measurement technique is a transient thermal method based on infrared thermography, which was thoroughly described and validated in a previous work. The influence of inlet freestream turbulence and blowing ratio was evaluated, and two different injection angles were considered for both pressure and suction sides. Spatially resolved distributions of adiabatic effectiveness and heat transfer coefficient (HTC) on the vane surface allow us to precisely quantify the above-mentioned aspects and highlight qualitative differences between pressure side and suction side behavior. Details regarding the generated non-uniformities in the measured parameters could be also provided, to emphasize how average quantities are not always sufficient to characterize such complex phenomena. The impact of different reference conditions to scale HTC results was also investigated. Such effect was found not negligible on the overall performance of the film-cooling system, especially on the suction side where transition plays a critical role. Ultimately, the collected results constitute a wide and detailed experimental database for numerical modeling validation in a well-studied environment as the LS89 configuration.

Co-adjustable guide vane and diffuser vane to improve the energy generation potential of an axial-flow pump as turbine

Operating an axial-flow pump as turbine (APAT) with a high head can be a cost-effective solution for energy recovery applications. However, axial-flow pumps are characterized by a low head, which makes it difficult for an APAT to achieve high efficiency. In this study, computational fluid dynamics–based numerical simulations were performed using steady and unsteady Reynolds-averaged Navier-Stocks equations and a shear stress transport reattachment modification turbulence model to investigate how the energy performance and operating range of an APAT can be improved under low-head conditions. The experiment was conducted to evaluate the accuracy and reliability of the numerical results. Adjusting the diffuser vane (DV) and guide vane (GV) were identified as candidate solutions. The adjusting mechanism was designed and presented in both 2D drawings and 3D model. Further simulations were performed to evaluate the effect of the clearances at the hub and shroud of the GV and DV. While the clearances at the GV had no adverse effect on the energy performance, clearances at the DV greatly reduced the energy performance because of the formation and growth of leakage vortex flows. Adjusting the DV improved the energy performance more than adjusting the GV. A co-adjustable GV and DV is a comprehensive solution that was found to increase the efficiency of the APAT by 40.15 % under low-head conditions and weaken vibration and noise by suppressing the separation flow in the GV domain.

Effect of the Guide Vane on the Hydraulic Stability of a Low-head, Large-discharge Industrial Hydraulic Turbine

The hydraulic turbine has been used extensively in the field of energy conservation. For turbines that have low heads and large discharge, improving recovery efficiency and stability is crucial due to their significant hydraulic impact. This paper provides a detailed analysis of the correlation between the influence of radial guide vanes on the stability of low-head, large-discharge turbines focusing on hydraulic performance and energy dissipation before and after the implementation of guide vanes. Moreover, in this paper, two types of turbines, with and without guide vanes, were designed considering the desulfurization scenario. Hydraulic efficiency, radial force, and internal flow field mechanics were numerically studied, and validated through experiments. The results reveal that the working range of the hydraulic turbine could be widened and the energy recovery efficiency improved by a maximum of 3.11% in the small flow rate under the action of guide vanes. Furthermore, it results in a substantial reduction in the radial force of the impeller. Subsequently, the variation in entropy production of different components under full flow rate conditions was compared between the models with and without guide vanes. The total energy consumption decreases sharply under overall working conditions due to the flow control ability of guide vanes affecting the flow state. The entropy production rate of the impeller remains the largest regardless of the presence of a guide vane in the turbine. The vortices inside the guide vanes increase obviously with the flow rate increase.

Design and CFD simulation of guide vane for multistage Savonius wind turbine

This study proposes improving the performance of a fixed-axis multistage Savonius wind turbine by integrating a sixbladed guide vane. Guide vanes aim to direct the incoming wind towards the blades of the Savonius wind turbine so that it can increase the performance value of the turbine itself. There are two methods, the first method is computational fluid dynamics (CFD) simulation to evaluate the best performance guide vane angle variations. The second method is implementing real conditions using 3 m/s until 4.2 m/s wind speed. The implementation of the guide vane to the wind turbine will consider four (4) variants of angles (0°, 20°, 40°, and 60°). The purpose of testing with four kinds of guide vane angles is to find out which guide vane angle can provide the best results among other guide vane angles. This research proposed the initial design of the guide vane addition to the multistage Savonius wind turbine with a fixed rotary axis. From the CFD simulation, the implementation of a guide vane can improve the performance of the multistage Savonius wind turbine with a fixed rotary axis. On the other hand, for the proposed initial design in this research, the 20° angle of guide vane gives the best result compared to the 0°, 40°, 60°, and without guide vane.

Transient coupling modeling and dynamic response analysis of hydraulic turbine governing system and shafting system

To address the challenges posed by the connection of new energy sources to the grid, pumped storage power stations (PSPSs) are required to frequently engage in transient processes to maintain load balancing and regulate grid frequency. It remains difficult, however, to evaluate the transient characteristics of the hydraulic turbine governing system (HTGS) and shafting system because of the lack of suitable models. This study seeks to address this challenge by establishing a transient turbine model based on the surface-cluster method and the shafting system transient coupling model, accounting for hydraulic-mechanical-electrical factors. HTGS and shafting systems' dynamic response characteristics are investigated under two small oscillation processes and eleven closure laws of guide vanes (CLGVs). The findings reveal that the shafting system vibration increases with the load drop during small oscillation processes. Conversely, sudden load increases reduce shafting vibration and the change of vibration is related to the force of the blade. Moreover, the study identifies that under the fast-slow two-phase CLGV, the maximum relative head and rotor radial amplitude increase with decreasing guide vanes (GV) opening of the turning point, while the change in maximum relative speed is opposite. Under the slow-fast two-phase CLGV, the maximum head and speed increase with decreasing GV opening of the turning point, while the maximum radial amplitude of the rotor is the opposite. Finally, under all the three-phase CLGVs, the transient characteristics of the head, speed, and shafting vibration under close-close-close (CCC) CLGV are the best. The innovation of this paper is to provide a method to establish the transient coupling model of HTGS and shafting, and to study the stability and transient response characteristics of HTGU.

The vortex dynamics characteristics in a pump-turbine: A rigid vorticity analysis while varying guide vane openings in turbine mode

In off-design conditions, pump-turbines generate vortex structures of varying scales and intensities, jeopardizing energy conversion due to unstable flow phenomena. While off-design pump-turbine internal flow dynamics have been analyzed, understanding the spatiotemporal evolution of complex vortex structures within runner blade passages, which are prone to inducing hydraulic instabilities, has to be still addressed properly. This paper applies the rigid vorticity theory, also known as Liutex, to explore vortex characteristics in the pump-turbine under different guide vane openings during turbine mode operation. The investigation focuses on three main aspects: i) spatial distribution characteristics, ii) temporal evolution characteristics, and iii) vortex morphological features along with deformation mechanisms. Results showed that the suction surface side of the blade's trailing edge commonly experiences significant shear effects, while vortices tend to emerge on both pressure and suction surface sides. Under small Guide Vane Opening (GVO) condition, vortices in blade passages show periodic evolution, and Enstrophy of the Rigid Vorticity Dilatation Term (ERDT) predominantly contributes to the helical deformation of these vortices. Conversely, under large GVO condition, vortices maintain high helicity and remain stable. This study provides insights to reduce hydraulic instability in pump-turbines and optimize energy conversion efficiency. The proposed Reynolds-averaged transport equation for enstrophy of the rigid vorticity and the relative streamline coordinate system provide advanced tools for analyzing unstable flow structures.