Impeller Rotational Speed Research Articles

Parametric Analysis of a Double Shaft, Batch-Type Paddle Mixer Using the Discrete Element Method (DEM)

To improve the understanding of the mixing performance of double shaft, batch-type paddle mixers, the discrete element method (DEM) in combination with a Plackett–Burman design of experiments simulation plan is used to identify factor significance on the system’s mixing performance. Effects of several factors, including three material properties (particle size, particle density and composition), three operational conditions (initial filling pattern, fill level and impeller rotational speed) and three geometric parameters (paddle size, paddle angle and paddle number), were quantitatively investigated using the relative standard deviation (RSD). Four key performance indicators (KPIs), namely the mixing quality, mixing time, average mixing power and energy required to reach a steady state, were defined to evaluate the performance of the double paddle mixer. The results show that the material property effects are not as significant as those of the operational conditions and geometric parameters. In particular, the geometric parameters were observed to significantly influence the energy consumption, while not affecting the mixing quality and mixing time, showing their potential towards designing more sustainable mixers. Furthermore, the analysis of granular temperature revealed that the centre area between the two paddles has a high diffusivity, which can be correlated to the mixing time.

FUZZY LOGIC-BASED MODELING OF A CENTRIFUGAL BLOOD PUMP PERFORMANCE VIA EXPERIMENTAL DATA OF NEWTONIAN AND NON-NEWTONIAN FLUIDS

Using fuzzy logic methods, some complex experiments that are not possible due to critical limitations can be simulated in a short time. In this study, experimental data of Newtonian 40% aqueous glycerin solution (GS) and non-Newtonian 600[Formula: see text]ppm aqueous xanthan gum solution (XGS) working fluids were used to model the hydraulic performance of a centrifugal blood pump. A novel fuzzy logic-based model (FLM) for modeling the hydraulic performance of the pump model is proposed. In the proposed model, there are two inputs which are flow rate and impeller rotational speed and one output which is head pressure. In FLM, the range for flow rate is 1–7.8[Formula: see text]L/min in GS and 1–8[Formula: see text]L/min in XGS, and for head pressure 50–245[Formula: see text]mmHg in GS and 50–215[Formula: see text]mmHg in XGS. In addition, impeller rotational speed range is 2700–3600[Formula: see text]rpm for both fluids. The estimated results with FLM were validated with the experimental results and it was seen that the FLM was compatible with the experimental results with an accuracy of 96.25%. These results imply that the developed FLM is acceptable and can be used to assist in determining the performance of blood pumps.

Physics-Based Reduced-Order Model for Liquid Ring Pumps

Abstract Liquid-ring vacuum pumps, by not having solid-solid contacts at interfaces where moving and stationary parts meet, are efficient and robust with considerable potential for further improvements on efficiency, performance, and range of operations. In this study, a physics-based reduced order model was developed for the preliminary design of liquid-ring pumps. The model developed accounts for the dominant physical processes created by the pump's key design and operating parameters: eccentricity, impeller-tip radius, impeller-hub radius, pressure at the pump's inlet and exit, and the impeller's rotational speed. The model developed can predict the shape of the liquid ring, the amount of air ingested and discharged by the pump, the power consumed by the pump as well as the pressure of the gas and liquid in the pump between the blades of the impeller as a function of those design and operating parameters. The predictions made by the model on the flow rates of the gas ingested by the pump and the power consumed by the pump were compared with experimental data, and good agreements were found.

A multi-field coupling simulation model for the centrifugal pump system

In this paper, a multi-field coupling simulation model, including the motor, shaft, and pump, is established to analyze the motor's influence and the shaft on the pump's operating status. First of all, different forms of simulation calculation models are established according to each device's characteristics. Then, the Predictor-Corrector Newmark- β method (PC Newmark- β method) is used to calculate the operating status of the motor, shaft, and pump under mutual influence. Finally, the validity of the simulation model is verified by comparing the experimental data. The results show that the centrifugal pump, shaft, and motor should be viewed as a complete system to analyze. The torque and speed of different equipment are interrelated and influenced. In addition, the dynamic characteristics of the shaft will also cause the fluctuation of the pump's operating speed. The fluctuation of the centrifugal pump impeller's rotational speed further affects the characteristics of the pressure pulsation on the wall of the centrifugal pump, which is finally reflected in the vibration characteristics of the pump casing.

Experimental mass and heat transfer at a serpentine tube heat exchanger located at the wall of a square stirred tank reactor

• Rates of mass and heat transfer of a serpentine tube heat exchanger were studied. • The serpentine is located at the wall of a square stirred tank reactor. • Variables studied were impeller speed and geometry, tube diameter, and tube pitch. • Dimensionless correlations were developed to design and operate the heat exchanger. • The possibility of using the serpentine tube as a catalyst support was highlighted. Although the study of the heat transfer behavior of stirred tank heat exchangers such as helical coils, vertical tube baffles, and cooling jackets has received much attention, no study has been reported on the heat or mass transfer behavior of serpentine tube heat exchangers, so the present work aims to study rates of mass and heat transfer (by analogy) at the outer surface of a serpentine tube heat exchanger located at the wall of a square stirred tank reactor by the electrochemical technique. Variables studied were impeller rotational speed, impeller geometry, tube diameter, and tube pitch. The mass or heat transfer coefficients were found to increase with increasing impeller speed and decrease with increasing cylinder diameter and pitch. For a given set of conditions, a radial flow turbine produces higher rates of mass transfer than an axial flow turbine. The data were correlated by dimensionless mass transfer correlations which can be used to scale up and operate the heat exchanger. When the mass transfer data at the serpentine tube were compared with those at an active flat wall of equal height, it was found that the mass transfer rate at the serpentine tube is higher than that of the flat wall by an amount ranging from 10% to 210% depending on the operating conditions. The possibility of using the serpentine tube as a catalyst support for conducting diffusion-controlled exothermic immobilized cell biochemical reactions which need rapid cooling to avoid thermal degradation of the biomass was highlighted. The dual-use of the serpentine tubes as a catalyst support and a cooler would reduce the capital and operating costs of immobilized enzyme or cell stirred tank biochemical reactors compared, for instance, with the traditional stirred slurry reactor owing to the elimination of the costly and time-consuming process of separating the final product from the catalyst particles.

ANALISA STRUKTUR DAN PERFORMA IMPELLER POMPA SENTRIFUGAL DENGAN MENGGUNAKAN COMPUTATIONAL FLUID DYNAMIC AND FINITE ELEMENT METHOD

Centrifugal pumps are divided into two main components, namely the impeller and the volute. The impeller is a rotating pump component, while the volute is a stationary pump component. The current problem in the industrial world is that the pump capacity that operates is not in accordance with the written capacity so that the pump does not work optimally. In addition, the structural analysis of the pump is minimally carried out so that damage to the pump often occurs. To overcome this, it is necessary to analyze the performance and structure of the centrifugal pump design using computational fluid dynamics and static structural analysis methods on variations in the number of blades & impeller rotation speed. The results of the CFD analysis obtained are validated using existing product specifications and studies that have been carried out. The maximum value of the resulting von-mises stress is 20,238 Mpa, the maximum value of the resulting strain is 0.00010133, while the maximum total deformation value is 0.051984 mm. The three maximum values ​​occur in the variation of the 7 blade impeller with a rotational speed of 1800 rpm.

Mass and heat transfer at a corrugated wall of a square stirred tank reactor and possible applications

ABSTRACT The electrochemical technique was used to investigate the effect of surface corrugations on the rate of mass and heat transfer (by analogy) in a stirred tank reactor. Impeller rotational speed, impeller shape, corrugation peak to valley height, and corrugation orientation (horizontal or vertical) were among the variables investigated. Depending on the operating conditions, surface corrugation increased the volumetric mass transfer coefficient by a factor ranging from 1.16 to 3.7. Mass transfer data were correlated with dimensionless correlations of an average deviation of ±4.2 and ±5.49 for radial and axial flow turbines, respectively. The significance of the dimensionless equations in determining the rate of heat transfer from the corrugated wall to a cooling jacket was emphasized.

Effect of operating factors on liquid–liquid mass transfer and dispersion pattern of sedimentary liquid in a mechanically stirred vessel

AbstractLiquid–liquid dispersion and mass transfer were investigated in mechanically stirred vessels without baffles by changing operation factors such as an impeller rotation speed, off‐bottom clearance, volumetric liquid ratio, etc. The dispersion regime was categorized into five groups: the sedimentary liquid was kept at the vessel bottom (I), partially elevated without any collision (II), partially dispersed by colliding with the impeller bottom (III), both liquids were partially dispersed by collisions with impeller blades (III’), and the sedimentary liquid was completely dispersed (IV). The dispersion switched to I → II → III → IV with the increasing rotation speed and decreasing off‐bottom clearance. The liquid–liquid mass transfer rate was significantly enhanced with the collision of the sedimentary liquid with the impeller bottom, and subsequently increased with the increasing rotation speed, volumetric liquid ratio, and vessel diameter and with the decreasing off‐bottom clearance. A multiple regression analysis method was applied to determine the mass transfer rates of III and III’.

Breakage Assessment of Lath-Like Crystals in a Novel Laboratory-Scale Agitated Filter Bed Dryer

Agitated filter bed dryer is often the equipment of choice in the pharmaceutical industry for the isolation of potent active pharmaceutical ingredients (API) from the mother liquor and subsequent drying through intermittent agitation. The use of an impeller to promote homogeneous drying could lead to undesirable size reduction of the crystal product due to shear deformation induced by the impeller blades during agitation, potentially causing off-specification product and further downstream processing issues. An evaluation of the breakage propensity of crystals during the initial development stage is therefore critical. A new versatile scale-down agitated filter bed dryer (AFBD) has been developed for this purpose. Carbamazepine dihydrate crystals that are prone to breakage have been used as model particles. The extent of particle breakage as a function of impeller rotational speed, size of clearance between the impeller and containing walls and base, and solvent content has been evaluated. A transition of breakage behaviour is observed, where carbamazepine dihydrate crystals undergo fragmentation first along the crystallographic plane [00l]. As the crystals become smaller and more equant, the breakage pattern switches to chipping. Unbound solvent content has a strong influence on the breakage, as particles break more readily at high solvent contents. The laboratory-scale instrument developed here provides a tool for comparative assessment of the propensity of particle attrition under agitated filter bed drying conditions.

Optimizing the performance of a single-shaft micro gas turbine engine by modifying its centrifugal compressor design

The purpose of this paper is optimizing the performance parameters of a single-shaft micro gas turbine with a power of about 150 kW at the design point by modifying its centrifugal compressor geometry. According to the physics of this problem, a hybrid optimization approach (including modern and numerical optimizers) was employed. The optimization was based on the numerical simulation of each geometry using a three-dimensional Reynolds Averaged Navier-Stokes solver. The geometric parameters of the centrifugal compressor impeller constituted the design variables and the Latin hypercube was employed for sampling. To reduce the cost of the numerical calculation, the neural network was chosen for approximate modeling of the design space. The physics of the optimization problem ahead was identified and a state-of-the-art optimization process was presented accordingly. Furthermore, a detailed discussion was conducted on the design space transparency, convergence criteria, and optimum design selection, the disadvantages of current optimization processes and the advantages of the present one were explained. NASA CC3 compressor was scaled down for the baseline engine, which is a 150 kW single-shaft gas turbine. This engine was optimized using the proposed optimization process and a significant improvement was achieved, where efficiency increased by 13.93% and power by 11.07%, and the specific fuel consumption decreased by 12.15%. Furthermore, despite the constant impeller tip diameter and rotational speed, in the optimum compressor, the mass flow increased by 2.22% and the pressure ratio by 29.62% compared to the baseline compressor, while the isentropic efficiency not only did not decrease but also increased slightly (0.2%). However, the operating range decreased by 12.64%.

Solid-liquid suspension in a stirred tank driven by an eccentric-shaft: Electrical resistance tomography measurement

Aiming at improving particle suspension performance in the stirred tank, the eccentric-shaft agitation and two-half-pitched-blade (THPB) impeller were proposed. The power consumption and suspension characteristics of THPB impellers under the eccentric-shaft, concentric and eccentric agitation schemes were experimentally studied. Effects of solid loadings and impeller rotation speeds were discussed. Results were compared with their counterparts of the two-flat-blade (TFB) impeller. It was found that, when running at the same rotation speed, although power consumption of eccentric-shaft agitation is large, its suspension performance is the best. When operated under the equal-power condition, for the eccentric-shaft agitation scheme, TFB has the best suspension performance. For the concentric and eccentric agitation schemes, THPB impellers behave better than TFB. Under the lower-than- N js condition, increasing rotation speed can improve the suspension performance. Given the simple design and good suspension performance of eccentric-shaft agitation, it is promising to be applied in the industries. • Development of the eccentric-shaft agitation scheme. • Electrical resistance tomography (ERT) measurements of solid-liquid suspension performance. • Comparison of performances among the concentric, eccentric and eccentric-shaft agitation schemes. • Discussion on the effect of impeller type, rotation speed and solid loading.

Mass and Heat Transfer at the Bottom of Cylindrical Unbaffled Stirred Tank Reactor and Possible Applications

Liquid-solid mass and heat (by analogy) transfer at the bottom of a cylindrical stirred vessel were studied by using the well-known electrochemical technique. Variables studied included the impeller geometry and its rotational speed. Results revealed that the radial flow impeller is preferable over the axial flow one in terms of mass transfer enhancement, additionally, increasing the impeller rotational speed led to an increase in the mass transfer coefficient. Results were correlated by dimensionless equations. Application of these equations in the design and operation of an improved catalytic biochemical reactor suitable for conducting diffusion-controlled immobilized cell (or enzyme) reactions was highlighted. These equations can serve in predicting the corrosion rate and corrosion allowance required to calculate the bottom thickness of the agitated vessel in its design stage. Furthermore, these equations can be used in estimating the heat lost from the tank bottom, accordingly, design an effective cooling jacket surrounding the agitated vessel bottom in case of exothermic biochemical reactions to avoid thermal degradation of the biomass.

Numerical Simulation of Axial-Flow Pump Cavitation Based on Variable Frequency Speed Regulation

In order to investigate the influence of variable voltage and variable frequency (VVVF) regulation on the cavitation performance of the axial-flow pump, numerical simulation and experiments were used to analyze the cavitation performance of an axial-flow pump under different VVVF modes. The VVVF modes were uniform acceleration with constant acceleration, variable acceleration with increasing acceleration, variable acceleration with decreasing acceleration, and its corresponding deceleration scheme. Furthermore, a comprehensive performance test rig was built for the pump to carry out cavitation visualization tests which verified the accuracy of numerical simulation. For the uniform acceleration scheme with constant acceleration, the change of flow field inside the impeller was stable, the expansion rate of cavitation was slow, and the growth rate of the cavitation volume was the slowest. For the variable acceleration scheme with decreasing acceleration, the cavitation extended rapidly due to the large initial velocity. For the variable acceleration scheme with increasing acceleration, cavitation extension was the slowest. The growth rate of the cavity volume of the two variable acceleration schemes was faster than that of the uniform acceleration scheme, and the changing trend was consistent. This feature indicates that the impeller rotation speed has a significant impact on cavitation, and excessive rotation speed will rapidly extend the cavitation. By monitoring the influence of cavitation on pressure distribution under VVVF, it was shown that the three acceleration schemes all produce large pressure fluctuation. For the uniform acceleration scheme with constant acceleration, the fluctuation range of pressure was more balanced, and the pressure dropped slowly. For the acceleration scheme with higher acceleration, the pressure fluctuation amplitude increased in the late stage of acceleration and the pressure decline speed accelerated. For the acceleration scheme with decreasing acceleration, the pressure showed a downward trend with violent fluctuations in the early stage and gradually tended to be flat in the late stage.

Energy loss mechanisms of transition from pump mode to turbine mode of an axial-flow pump under bidirectional conditions

Pump-as-turbine stations with ultra-low head often face the deterioration risk during load rejection operations when the demands in water delivery and power generation are satisfied. In the course of load rejection, significant energy transfer and hydraulic instability may ensue from the pump-to-turbine transition mode, and vice versa. In order to investigate the variation of energy loss during the transition process of a bidirectional axial-flow pump, the entropy production method is herein utilized for visualization and quantitative analysis of high energy loss regions within key components. In the process of transient simulation, the torque balance equation is applied for calculating the rotational speed of impeller. Two-way transitions are considered with the bidirectional pump for comparing two distinct forms of pumps equipped with front and rear guide vanes. Results show that the simulated external characteristic curves and transition parameters of the pump are in good accordance with the experimental data. The transient process of the transition successively goes through four modes, i.e. pump, braking, turbine and runaway modes. In the process of the direction switch of the main flow and rotation, the different positions of guide vanes also deeply influence the inflow angle and flow pattern in impeller, and then change the distribution of the pressure coefficient, vorticity and entropy production rate. In pump mode, the entropy production rate and pressure coefficient at the impeller inlet edge under backward transition condition (BTC) is higher than that under forward transition condition (FTC), due to the smaller inflow angle caused by the front guide vanes under BTC. In runaway operation, the total entropy production (TEP) under FTC is obviously higher than that under BTC, because the energy loss is reduced by the broken shedding vortices caused by the obstruction of the guide vanes under BTC. This study's results can be referred to while seeking for the operation safety and stability of the pump stations consecutively used to pump and generate power.

Effects of operation parameters on particle mixing performance in a horizontal high shear mixer

Abstract Particle mixing is an important unit operation in many industry processes. This work employed the discrete element method (DEM) to characterize the mixing performance of iron ore particles in a horizontal high shear mixer. The simulation results were first compared with the positron emission particle tracking (PEPT) data reported by Forrest et al. to validate the DEM model. Then the effects of key operation factors such as impeller rotation speed, number of impellers and filling ratio on the mixing efficiency were discussed. The Lacey mixing index was employed to evaluate the mixing performance. The results show that the mixing efficiency of particles increased with increasing the number of impellers and their rotation speeds. On the other hand, the filling ratio was negatively related to the particles velocity and the mixing efficiency. This was because the effective space left for free movement of particles decreased as the filling ratio increased, and the mixing of particles was therefore restricted. In addition, the mixing rate of particles in the axial direction of the high shear mixer was much slower than that in the radial direction.

Effect of ultrasonic melt treatment conditions on melt quality of Al–Mg alloy

In this study, the effect and mechanism of ultrasonic melt treatment (UST) were studied to achieve high-quality molten Al–Mg alloy. The purpose was to analyze the change in the cleanliness of molten aluminum according to UST process conditions such as ultrasonic power, treatment duration, and stabilization duration for molten Al–Mg alloy, and to find the optimal ultrasonic process conditions to achieve high-quality molten aluminum. UST results were compared to the effect of the Gas Bubbling Filtration (GBF) process, which is a general molten aluminum treatment process. Density index, bifilm index, porosity, and X-ray CT analysis were used for quality evaluation of melt cleanliness. UST was performed at a frequency of 19.7 kHz and two outputs of 600 W and 1200 W after maintaining 1 kg of molten aluminum at 800 °C for 10 min. The UST treatment durations were 1, 3, and 5 min, the stabilization durations after treatment were 0, 10, and 20 min. Then the quality of the molten aluminum was measured. The GBF treatment was applied for 1, 5, 10, or 30 min under impeller rotation speed of 300 rpm and gas flow rate of 1 L/min. During UST, the melt quality improved as the ultrasonic power increased and the treatment duration increased. To secure the high melt quality, UST could obtain the required degassing effect after 3 min of treatment, whereas GBF treatment took 10 min. The bubble size generated by UST is smaller than that by GBF, so UST has higher mas transfer coefficient of hydrogen than GBF and hydrogen in the melt could be removed with only a short UST treatment. UST was superior to GBF immediately after treatment, however, the melt quality deteriorated during the stabilization after UST. It caused from the unstable oxide film and a relatively rapid high-temperature oxidation, so appropriate molten metal management and rapid post-processing are necessary after UST treatment.

Scale-up study of aerated coaxial mixing reactors containing non-newtonian power-law fluids: Analysis of gas holdup, cavity size, and power consumption

The use of coaxial mixers has significantly improved gas dispersion in non-Newtonian fluids. However, to the best of our knowledge, no scale-up investigation of an aerated coaxial mixer has been reported in the literature. This study aims to explore the gas hold-up, energy dissipation rate, power consumption and cavity size in order to provide the guideline for scaling-up of the coaxial mixers. Through the use of computational fluid dynamics and electrical resistance tomography, the effects of the aeration rate, central impeller type, rotating mode, impeller speed, and pumping direction on the gas dispersion efficacy in both small-scale and large-scale coaxial mixers containing non-Newtonian fluids were investigated. For the coaxial mixer in the co-rotating mode, the same flow regime was achieved when the central impeller tip speed and the anchor impeller rotational speed were kept constant in both small-scale and large-scale systems. It was observed that maintaining the aeration rate per volume of the non-Newtonian fluid constant was beneficial to preserve the performance of the large-scale coaxial mixer the same as its small-scale counterpart. The use of specific power consumption as a scale up criterion effectively improved the energy dissipation rate uniformity, which is critical for shear sensitive applications.

Effect of ultraviolet-C light-emitting diode irradiation on inactivation of white colony-forming yeast in kimchi seasoning

The presence of white colony-forming yeasts (WCFYs) in raw materials negatively affects the quality of kimchi. Accordingly, disinfection processes to effectively control spoilage yeasts, including WCFYs, are crucial for extending the shelf life of kimchi. However, conventional disinfection procedures could result in undesirable changes in the nutritional attributes or sensory characteristics of the food. Therefore, in this study, we investigated whether ultraviolet-C light-emitting diode (UVC-LED) treatment combined with an impeller system could inactivate Candida sake and Kazachstania servazzii cells without causing significant variations in the physicochemical characteristics of kimchi seasoning. UVC-LED at 1680 mJ/cm2 combined with the impeller system at 70 and 140 rotations per min (rpm) reduced the number of C. sake cells in kimchi seasoning by 2.29 and 2.79 log10 CFU/g, respectively, whereas the reduction in the number of K. servazzii cells was observed to be < 2 log10 CFU/g. After UVC-LED irradiation up to 1680 mJ/cm2, the changes in titratable acidity, pH, viscosity, and volatile compounds of the kimchi seasoning remained mostly constant (p > 0.05). We observed that the efficacy of UVC-LED treatment increased as the impeller rotation speed increased. K. servazzii was more resistant to UVC-LED irradiation than C. sake. These experimental results demonstrate that UVC-LED treatment may be a practical alternative to the limited disinfection approaches for high-quality kimchi production.

Experimental investigation on performance test of 150-kW-class supercritical CO2 centrifugal compressor

• Supercritical CO 2 compressor is designed and manufactured for performance test. • Centrifugal impeller is adopted to accomplish optimum design of supercritical CO 2 compressor. • Reliability of designed compressor is confirmed through repeated compressor performance test. • Effects of controlling of control valve and impeller rotation speed are analyzed. Supercritical CO 2 is a promising working fluid for next generation power conversion systems. The key component in a supercritical CO 2 power generation system is turbomachinery, which particularly includes the compressor. Supercritical CO 2 has high density and low compressibility, similar to the liquid state near the critical point. Therefore, when the compressor is operated near the critical point of CO 2 , significant reduction of compression work can be attained, as compared to conventional air Brayton cycles. However, there are technical challenges concerning the design and operation of the compressor. Therefore, in this experimental study, a 150-kW-class supercritical CO 2 centrifugal compressor for a 500-kW power generation system is designed and investigated. The design point of compressor, pressure ratio, and efficiency, are 1.75, and 80% at rotational speed 36000 RPM. The purpose of this test is to evaluate the performance of the supercritical CO 2 centrifugal compressor and obtain accessible fundamental data. During the performance test, which is conducted by controlling the rotational speed of the impeller and the opening rate of the control valve, the compressor is operated by an electric motor, and the generated pressure from the compressor is consumed using a control valve. Repeated tests are conducted on the compressor to confirm the practicality of the designed compressor for the supercritical CO 2 power generation system. The compressor achieves a higher efficiency of 80% than the target efficiency during the repeated four tests. In addition, the reliability of the compressor performance is examined. Furthermore, the results of the test are analyzed to understand the effects of the opening rate of the control valve for load changing and the rotational speed of the impeller.

Computational Fluid Dynamics Model of Continuous-Flow Total Artificial Heart: Right Pump Impeller Design Changes to Improve Biocompatibility.

Cleveland Clinic is developing a continuous-flow total artificial heart (CFTAH). This novel design operates without valves and is suspended both axially and radially through the balancing of the magnetic and hydrodynamic forces. A series of long-term animal studies with no anticoagulation demonstrated good biocompatibility, without any thromboemboli or infarctions in the organs. However, we observed varying degrees of thrombus attached to the right impeller blades following device explant. No thrombus was found attached to the left impeller blades. The goals for this study were: (1) to use computational fluid dynamics (CFD) to gain insight into the differences in the flow fields surrounding both impellers, and (2) to leverage that knowledge in identifying an improved next-generation right impeller design that could reduce the potential for thrombus formation. Transient CFD simulations of the CFTAH at a blood flow rate and impeller rotational speed mimicking in vivo conditions revealed significant blade tip-induced flow separation and clustered regions of low wall shear stress near the right impeller that were not present for the left impeller. Numerous right impeller design variations were modeled, including changes to the impeller cone angle, number of blades, blade pattern, blade shape, and inlet housing design. The preferred, next-generation right impeller design incorporated a steeper cone angle, a primary/splitter blade design similar to the left impeller, and an increased blade curvature to better align the incoming flow with the impeller blade tips. The next-generation impeller design reduced both the extent of low shear regions near the right impeller surface and flow separation from the blade leading edges, while maintaining the desired hydraulic performance of the original CFTAH design.