Disk Pump Research Articles

The influence of the disk pump of assisted circulation of the left ventricular bypass on hemolytic blood parameters

The influence of the disk pump of assisted circulation of the left ventricular bypass on hemolytic blood parameters

Analysis of Ingress Into the Downstream Wheel Space of a 1.5-Stage Turbine By Full Circumference and Single Blade Passage Large-Eddy Simulations

Abstract The flow in a 1.5-stage axial turbine is investigated by large-eddy simulations. The focus is on the ingress in the downstream wheel space. Two setups are considered. In the first, the full 360 deg annulus is included on a computational mesh with approx. 1 billion mesh cells. The second setup includes a single blade passage in a 22.5 deg segment. The computational mesh has approx. 75 million mesh cells accordingly. The flow fields in the downstream wheel space differ strongly. In the 22.5 deg setup, the disk pumping effect is much more pronounced than in the 360 deg setup and the fluid bulk rotates in the direction of the rotor rotation. In the 360 deg setup, the fluid rotates in the opposite rotor direction and the velocities feature a deflection at intermediate radii. The differences are caused by the instantaneous flow fields. In the upstream wheel space of the 360 deg setup, two large-scale rotating vortex structures are predicted, which create four pressure peaks that propagate downstream. They interact with the second stator and create a rotating flow structure in the downstream wheel space, which generates alternating ingress and egress. Due to their spatial extent, none of these structures can exist in the 22.5 deg setup. The results show that for the investigated combination of turbine geometry and operating condition, the analysis of the downstream wheel space requires the detailed prediction of the unsteady flow phenomena in the upstream wheel space, i.e., it cannot be performed using the 22.5 deg setup.

Numerical simulation of gas-liquid two-phase flow in a disc pump under different inlet bubble diameters

Visual investigation and numerical simulation were utilized to analyze the internal flow pattern transformation and bubble diameter variation of a gas-liquid two-phase flow disc pump. The results reveal that increasing the intake volume fraction (IGVF) from 1.12% to 27.67% changes the flow pattern in the suction chamber from bubbly to agglomerate bubbly, slug flow, and separated flow. Due to the particularity of the impeller structure of the disc pump, the blades in the leaf area of the front and rear cover plates play a barrier role. The gas phase gathers most violently at the edge of the blade in the leaf area, while the flow channel in the middle leafless area is wider and has higher permeability. At 1500r/min and 7.11% inlet volume void fraction, the local void fraction extreme value of the front edge of the blade in the blade area of the front cover plate increases to three times the initial void fraction, while the void fraction extreme value of the middle section of the bladeless area decreases to two-thirds of the initial void fraction. This research can be used to analyze the gas phase distribution and migration law in the disc pump impeller.

Comparative analysis of internal flow characteristics and particle trajectories of centrifugal pumps with different impeller structures under solid-liquid two-phase flow conditions

The disc pump is a non-conventional centrifugal pump that utilizes centrifugal force and boundary layer effects to transport fluids. This pump is widely used in industries such as petrochemicals. However, due to the presence of particles in the solid-liquid two-phase flow, it causes wear and performance degradation of the pump’s flow components. However, due to the presence of particles in the solid-liquid two-phase flow, it can cause wear and performance degradation of the pump components. To study the internal flow characteristics of solid-liquid flow and the particle trajectory in a bladed disc pump, numerical simulation method was adopted to perform steady-state numerical simulation of spherical particles with different diameters (0.1 mm, 0.25 mm, 0.4 mm) in the bladed disc pump. The results indicate that compared to conventional centrifugal pumps, the performance of the bladed disc pump is lower. The variation in particle diameter has a minor influence on the intensity of the internal flow field in the bladed disc pump. The particle trajectories inside the impeller of the bladed disc pump are more chaotic, with larger diameter particles exhibiting a wider range of trajectory variations, while smaller diameter particles maintain relatively stable motion trajectories.

Blade Number Effects in Radial Disc Pump Impellers: Overall Performances with Cavitation Sensitivity Analysis

Straight radial impeller disc pumps are widely used in several industrial applications for hard-to-pump working flow media, such as two-phase inlet conditions, either including non-miscible bubbles or solid particles with a high concentration within the main working flow. Compared with conventional pump designs, these pumps have not been widely studied, because of their particular simple design and low efficiency values that can however reach a maximum value of 0.5 with a good pressure increase in single-phase conditions. Regarding this, no basic analysis has been performed to build one-dimensional design rules considering the relative effects of design parameters proper to these unusual designs like the blade number, blade height and disc spacing. This step is an important one for two-phase flow performance evaluations which are usually derived from single-phase ones as for conventional pumps. Two different disc pump designs with, respectively, 8 and 10 radial blades, are numerically and experimentally investigated. Experimental investigations are performed in an open loop tap water test facility, under various working conditions, combining flow rate and rotational speed variations. The overall pump performances are compared and analyzed, including cavitation onset phenomena that have been found to influence the experimental performances of both pumps. The overall performance modification between both impeller designs is analyzed. Comparisons between CFD and experimental results give reliable results and can be considered to cover a sufficiently wide range of design parameters allowing us to build future adapted design rules for such specific designs.

Research on Energy-Efficient Disc Pumps: A Review on Physical Models and Energy Efficiency

Disc pumps have obvious advantages in dealing with difficult-to-pump media. Energy efficiency and sustainable energy management are important topics with regard to reducing costs and promoting carbon neutrality. Though the concept of the disc pump was proposed in the 1850s, development was slow and limited by its initial model. However, with the development of industries such as petrochemicals and food, the efficient pumping of difficult-to-pump media is much needed, but facing challenges. Therefore, research on energy-efficient disc pumps is particularly important moving forward. In this paper, the available information from the open literature about the research and development of the disc pump will be thoroughly reviewed. It focuses on the historical development, energy efficiency and physical model application of the disc pump. The review ends with a proposal for the direction of future development, and in this aspect, it is proposed that the energy efficiency prediction model based on velocity slip theory, the energy management system based on multi-scenarios and the design method based on energy conversion theory are important. The latest achievements in energy conversion are given. This review also provides a new perspective for the development of energy-efficient disc pumps.

Modeling of the operation of a disc pump with the wall roughness consideration

Background: at present, a small number of studies of disk pumps operating on a low-viscosity liquid have been conducted. In addition, among the existing works, numerical calculations are presented, which have a serious discrepancy with the experiments carried out. This article is devoted to numerical simulation of the operation of a disk pump on water, comparison of the calculation results with experimental data.
 Aims: to determine the factors affecting the convergence of the main characteristics with experimental data when performing CFD calculations on a low-viscosity liquid.
 Methods: in this paper, a numerical modeling method based on the solution of discrete analogs of the basic equations of hydrodynamics is used. To compare CFD calculations with the experiment, a test bench was created on which two configurations of the impeller were studied.
 Results: it is shown that for this type of dynamic machines, it is important to take into account the influence of the roughness of solid walls when modeling their operation on a low-viscosity liquid, since it has a significant effect on the characteristics of the disk pump. The obtained characteristics are compared with experimental data, as well as flow patterns in the flow part.
 Conclusions: based on the results of the article, it can be argued that taking into account roughness in numerical calculations of a dynamic pump has a positive effect on convergence with experimental data.

Self-gravity of debris discs can strongly change the outcomes of interactions with inclined planets

ABSTRACT Drastic changes in protoplanets’ orbits could occur in the early stages of planetary systems through interactions with other planets and their surrounding protoplanetary or debris discs. The resulting planetary system could exhibit orbits with moderate to high eccentricities and/or inclinations, causing planets to perturb one another as well as the disc significantly. The present work studies the evolution of systems composed of an initially inclined planet and a debris disc. We perform N-body simulations of a narrow, self-gravitating debris disc, and a single interior Neptune-like planet. We simulate systems with various initial planetary inclinations, from coplanar to polar configurations considering different separations between the planet and the disc. We find that except when the planet is initially on a polar orbit, the planet–disc system tends to reach a quasi-coplanar configuration with low vertical dispersion in the disc. When present, the Zeipel–Kozai–Lidov oscillations induced by the disc pump the planet’s eccentricity and, in turn, affect the disc structure. We also find that the resulting disc morphology in most of the simulations looks very similar in both radial and vertical directions once the simulations are converged. This contrasts strongly with massless disc simulations, where vertical disc dispersion is set by the initial disc-planet inclination and can be high for initially highly inclined planets. The results suggest caution in interpreting an unseen planet’s dynamical history based only on the disc’s appearance.

Differentiation of Body Fluid Stains Using a Portable, Low-Cost Ion Mobility Spectrometry Device-A Pilot Study.

The identification and recovery of suspected human biofluid evidence can present a bottleneck in the crime scene investigation workflow. Crime Scene Investigators typically deploy one of a number of presumptive enhancement reagents, depending on what they perceive an analyte to be; the selection of this reagent is largely based on the context of suspected evidence and their professional experience. Positively identified samples are then recovered to a forensic laboratory where confirmatory testing is carried out by large lab-based instruments, such as through mass-spectrometry-based techniques. This work proposes a proof-of-concept study into the use of a small, robust and portable ion mobility spectrometry device that can analyse samples in situ, detecting, identifying and discriminating commonly encountered body fluids from interferences. This analysis exploits the detection and identification of characteristic volatile organic compounds generated by gentle heating, at ambient temperature and pressure, and categorises samples using machine learning, providing investigators with instant identification. The device is shown to be capable of producing characteristic mobility spectra using a dual micro disc pump configuration which separates blood and urine from three visually similar interferences using an unsupervised PCA model with no misclassified samples. The device has the potential to reduce the need for potentially contaminating and destructive presumptive tests, and address the bottleneck created by the time-consuming and laborious detection, recovery and analysis workflow currently employed.

The Arrangement and Cross-sectional Shape of Cooling Fins on Train Brake Discs

Taking into account physical factors such as the wind effect of the brake disc pump, heat dissipation power, and temperature rise, the optimal cross-sectional shape and layout of the brake disc cooling fins are studied. The flow field distribution and pump-wind heat dissipation power ratio of four different cross-sectional shapes, namely circular, elliptical, square, and rhombic, are compared and analyzed. The flow characteristics, wind effect, and heat dissipation power of the cooling fins under two different layouts, namely crosswise and parallel layouts, are also analyzed. The research results show that the circular cooling fins have the optimal pump-wind loss and heat dissipation power, and the crosswise layout of cooling fins shows the best comprehensive performance. The performance analysis method of cooling fins obtained in this paper provides a reference for the optimization design of brake disc structures.

Empirical formulas for calculating the characteristics of centrifugal disk pumps

Empirical formulas for calculating the characteristics of centrifugal disk pumps

Internal Cavitating Flow Distribution and Performance Comparison of a Disc Pump with Radial Straight Blade

Disc pumps with radial straight blade are unconventional designs that have been developed for hard-to-pump mixtures for many industrial applications. They are frequently used in chemical industries, sub-sea petroleum pumping systems with multi-phase media and so on. Due to the radial straight blade arrangement, they may suffer from cavitation onsets when being used under different pressure conditions. To study the influence of cavitation characteristic inside the present disc pump flow passages, experimental data analysis on a radial blade disc pump for a wide flow rate range (0 to 110 m3/h) is obtained. In addition, the Reynolds averaged (RANS) approach using the RNG k-ε turbulence model, is carried out under different working conditions with and without cavitation modelling. Two different pump meshing models are also implemented: the first one without hub and shroud side channels between the discs and the volute casing, the second one with both side channels corresponding to the complete real case geometry. The comparisons between experimental and numerical results reveal first that the complete geometry meshing must be used to recover the experimental performance curve especially at low flow rates whatever the rotational speed. Secondly, the cavitation effect is found to take place in precise locations (straight blade and connection column) inside the impeller at high rotational speed and high flow rates. Their effects correspond to the unexpected performance curve deterioration found for the highest rotational speed and high flow rates. Moreover, with the decrease of the inlet absolute pressure, the cavitation degree becomes serious, and the coupling phenomenon of straight blade cavitation and connection column cavitation is formed, which enlarges the scope and enhances the degree of cavitation. The present study proposes a data reduction procedure when open loop experimental testing procedure is used for specific disc pump design and the importance of the impeller-side channels interactions on head pump decrease at low flow coefficients.

Analysis of the Efficiency of Disk Pumps

Analysis of the Efficiency of Disk Pumps

A New Interpretation of Hot Gas Ingress Through Turbine Rim Seals Influenced by Mainstream Annulus Swirl

Abstract Rim seals are fitted at the periphery of the stator and rotor disks to reduce the adverse effects of hot gas ingress on highly stressed turbine components limited by temperature. Ingress is induced by rotational effects such as disk pumping, as well as by asymmetric pressure-driven unsteady phenomena. These influences superpose to form a complex flow-physics problem that is a challenge for computational fluid dynamics. Engine designers typically use practical low-order models that require empirical validation and correlating parameters. This paper identifies the swirl ratio in the mainstream annulus as a dominant characterizing parameter to predict ingress. This is a new interpretation that is supported by extending a low-order model based on turbulent transport using an effective eddy mixing length based on the difference in swirl between the annulus and seal clearance. Experimental measurements were made using a 1.5-stage turbine rig at low Reynolds number. The influence of annulus swirl ratio was investigated over a range of flow conditions and two rim-seal geometries, with the ingress quantified using CO2 tracer concentration in the sealing flow. The concentration data were complemented by measurements in the annulus using a five-hole aerodynamic probe.

Parameters of Ionic and Acid-Base Balance during Assist Circulation with a LVAD Disc Pump.

In chronic experiments on calves, the effect of the left-ventricular assist device (LVAD) technique by using a disc pump on the indicators of ionic and acid-base homeostasis. At blood velocity of 20% from the total volume, a trend towards an increase in K+ concentration and a slight decrease in the concentration of Na+, pH, and standard base excess in animal plasma were observed. If the blood velocity increased up to 90%, the indicators of ionic and acid-base homeostasis returned to their baseline values. In parallel, stroke volume and cardiac output as well as BP at the outlet of the heart and inside it and HR increased simultaneously with a blood pressure decrease in the input cannula site. There were no differences in plasma concentrations of Ca2+ and Cl- at different blood flow volumes.

Study on hydraulic characteristics and internal flow mechanism of composite blade disc pump

Abstract Disc pump is widely used in difficult-pump-medium transportation such as petroleum and chemical industry. Discontinuous blade impellers play an important role in the passability and energy efficiency of disk pump. The research of design and internal flow mechanism are particularly important. Based on the structural characteristics and the internal flow mechanism of the original model, the improved design of the blade structure is carried out. Through the experimental verification and the numerical analysis of multiple working conditions, the influence law of the new composite blade on the hydraulic characteristics and internal flow mechanism of the disc pump is obtained. The results show that the error of energy efficiency characteristics of simulation and experiment under different flow conditions is within 5%, and the accuracy of simulation results meets the requirements; The hydraulic characteristics of the improved model are about 5.8% higher than that of the original model. The driving force of the new composite blade is more sufficient and the flow field is improved more obviously; The low pressure is located in the center of the impeller and gradually increases to the outlet of the impeller. There is obvious energy and mass conversion between the bladed region and bladeless region. The research results can provide a reference for the structural design of disc pump composite blade and the analysis of internal flow mechanism.

An Analysis on Hydraulic Loss in a Co-Rotating Bladed Disc Pump

Disc pumps rely on the shear force generated by a co-rotating disc to transport the fluid, the interaction between the fluid and impeller is weak, providing such pumps advantages when handling multi-phase flow. In the present study, a loss analysis is presented on a different kind of disc pump that combines both shear and pressure forces using a co-rotating disc pump and radial blades and that is often applied in marine petroleum engineering for mud-lifting. Experimental measurements on the overall pump performance were performed, and the subsequent hydraulic efficiency analysis shows that similarity laws can be applied for this pump. A particular analysis was specifically performed on the impeller and shows that the resulting loss analysis indicates that the increase in the static pressure is small and that the total pressure increase is mainly contributed to by the dynamic pressure change from the inlet to the outlet impeller sections. In addition, an evaluation of the individual loss levels is proposed in the impeller that is based on one-dimensional assumptions. This type of evaluation has never been proposed for present specific TBD pump designs in the available literature. The obtained results showed that the most important loss levels are roughly equally distributed between the incidence effects, inter-blade leakage, and bolts losses in the impeller, and that all together, they can reach 80% of the total impeller losses, while the blade-loading and friction losses are relatively small. The losses downstream of the impeller are significant; thus, a specific volute design that has been adapted for a disc impeller outlet flow pattern must be considered in order to achieve better performance. The present loss analysis was able to predict the corresponding disc pump performance well, achieving a maximum error rate of ±5% for a rather wide flow coefficient range. The proposed method can be considered to be a useful approach for research or for industrial teams who are working on the same kind of geometry by adopting the same data reduction analysis, allowing them to compare their own results with the present ones.

Irreversibility analysis in hydromagnetic Reiner-Rivlin nanofluid with quartic autocatalytic chemical reactions

The theme of this paper is to scrutinize the irreversibility analysis in hydromagnetic flow of Reiner-Rivlin nanoliquid due to stretching rotating disk. Entropy expression is developed by first and second laws of thermodynamics. Joule heating, radiation and dissipation are scrutinized. Brownian and thermophoresis diffusion characteristics are addressed. Here our main aim is to discuss entropy and thermal transportation analyses. Furthermore isothermal quartic autocatalytic chemical reactions are discussed at catalytic surface. Partial differential equations (PDEs) are reduced to ordinary one (ODEs). ND-solve method is used to get convergent solutions for the obtained ordinary differential equations. Characteristics of different sundry variables on thermal field, velocity, concentration and entropy generation rate are discussed. Skin friction, moment coefficient disk pumping efficiency (entrainment velocity) and Nusselt number against various influential variables are analyzed through Tables. An opposite trend is noticed for both velocity and temperature distribution for magnetic parameter. Higher Reiner-Rivlin liquid parameter improves the radial and axial velocity components. Similar impact is observed for both temperature distribution and entropy generation against magnetic parameter and Brinkman number. An increment in concentration is noted against thermophoresis parameter. Larger estimation of radiation variable leads to augments the temperature distribution. A reduction occurs in entrainment velocity (pumping efficiency) and moment coefficient versus fluid variable. Higher stretching parameter leads to reduce the skin friction coefficient.

Handling dilatant isocyanates

One of the most hard-to-handle liquids is dilatant isocyanates as it is both sensitive and hazardous. This article examines why eccentric disc pumps have become popular for the production and handling of these and other classes of dilatant fluids.

Entropy optimized flow of Reiner-Rivlin nanofluid with chemical reaction subject to stretchable rotating disk

The theme of this article is to address the irreversibility in an incompressible Reiner-Rivlin nanofluid subject to stretchable rotating disk. Dissipation and radiation in heat expression are incorporated. Random diffusion and thermophoresis impacts are addressed. Physical feature of entropy rate is also accounted. Furthermore, first order reaction rate is scrutinized. Ordinary system (ODEs) is obtained through implementation of suitable variables. To construct convergent solution, we employed numerical method (ND-solve method). Outcomes for flow variables on velocity profile, thermal field, concentration and entropy optimization are discussed. Computational outcomes of moment coefficient, skin friction coefficient, entrainment velocity (disk pumping efficiency), Sherwood number and gradient of temperature versus sundry variables are studied. An expansion in radial velocity is observed for Reiner-Rivlin fluid variable. An augmentation in stretching parameter leads to opposite behavior of radial and tangential velocity components. An amplification in temperature distribution and entropy rate are observed for radiation variable. An improvement in thermophoresis parameter augments concentration and temperature distribution. Higher approximation of Brinkman number rises entropy generation rate.