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Effects of the number of blades on the impeller-volute interaction and flow instability were studied for a centrifugal pump. The hydraulic performance and time-dependent flow field were analyzed by using the unsteady three-dimensional Reynolds-averaged Navier-Stokes equations with the k-ω based shear stress transport turbulence model. The grid dependence and temporal resolution were tested to evaluate the numerical uncertainties, and the numerical results were validated using experimental data. As the performance parameters, the stage total-to-static head coefficient, the impeller total-to-static head coefficient, and the volute static pressure recovery coefficient were selected to classify the cause of the impeller-volute interaction and flow instability observed inside components. Using the fast Fourier transform, fluctuations of the performance parameters were divided into three categories: the blade passing frequency and its harmonic frequencies, the fluctuations in the broadband frequency region, and the fluctuations in the low-frequency region. The results showed that the fluctuations of the performance parameters and local pressure were affected in various ways by the number of blades. The time-dependent flow structure was investigated to study the root causes of the differences in the impeller-volute interaction and flow instability by the number of blades.

Micromixers are important components of lab-on-a-chip systems, and also have many biological and chemical applications [...]

The paper presents a numerical investigation on the junction flow occurring at the intersection between a wall and a protruding circular cylinder. Simulations of flow for Reynolds number ( Re) in the range [125 - 20000] have been carried out using OpenFOAM, an open source CFD tool. Plots of stream tracers have been used to qualitatively characterize the flow topology as either attachment or separation based on the type of singular points, classified as nodes and saddle points. Quantitative variations of momentum flux have been applied to identify a key mechanism for the transition of topology using the relative momentum strength of the incoming and reverse flow. Effect of a thinner boundary layer has been assessed by (i) imposing a reduced wall shear stress, and (ii) increasing the Reynolds number. Features of a typical unsteady flow, in the transition regime, at Re = 20000 have been predicted using Large Eddy Simulation (LES) with a one-equation eddy viscosity sub-grid scale model. Description of the time evolution of the topology at Re = 20000 has been able to validate the one-equation model in OpenFoam as well as to further validate the key mechanism identified for topology transition.

In this study, a numerical investigation based on the CFD method is carried out to study the unsteady laminar flow of Newtonian fluid with a high viscosity in a three-dimensional simulation of a twisted double planetary mixer, which is composed of two agitating rods inside a moving tank. The considered stirring protocol is a “Continuous sine squared motion” by using the dynamic mesh model and user-defined functions (UDFs)to define the velocity profiles. The chaotic advection is obtained in our active mixers by the temporal modulation of rotational velocities of the moving walls in order to enhance the mixing of the fluid for a low Reynolds number and a high Peclet number. For this goal, we applied the Poincaré section and Lyapunov exponent as reliable mathematic tools for checking mixing quality by tracking a number of massless particles inside the fluid domain. Additionally, we investigated the development of fluid kinematics proprieties, such as vorticity, helicity, strain rate and elongation rate, at various time periods in order to view the impact of temporal modulation on the flow properties. The results of the mentioned simulation showed that it is possible to obtain a chaotic advection after a relatively short time, which can deeply enhance mixing fluid efficiency.

In this study, a spiral ring cavity (SRC) is proposed to improve the operational stability of a centrifugal compressor. Aerodynamic performance of the compressor was analyzed using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. To prove the superiority of the proposed cavity, adiabatic efficiency and stall margin of an SRC were compared with those of the smooth casing and conventional cavities, i.e., ring cavity and discrete ring cavities. To find the optimum shape of the cavity, a parametric study was performed for the SRC using three geometric parameters, i.e., the axial location, width of the cavity port, and circumferential location of the SRC. The operation stability was sensitive to the width of cavity port and circumferential location. The SRC improved the stall margin considerably compared to other cavities.

This study investigates the effects of inlet guide vane (IGV) and blade pitch angles on the steady and unsteady performance of a submersible axial-flow pump. To analyze the interaction between the IGVs and the rotor blades, both steady and unsteady three-dimensional Reynolds-averaged Navier-Stokes equations were used with shear stress transport turbulence closure. Hexahedral meshes were used in the computational domain. The numerical results for performance curves showed good agreement with experimental data. The results showed that the steady and unsteady performance characteristics were dependent on both the IGV and blade pitch angles. Adjusting these angles affected the total pressure rise and thus caused variation in the efficiency in overload conditions. But adjusting these angles affected the unsteady pressure fluctuations in partial-load conditions. Detailed flow analyses were performed to find the root-cause of these phenomena.

In this work, a numerical investigation was analyzed to exhibit the mixing behaviors of non-Newtonian shear-thinning fluids in Kenics micromixers. The numerical analysis was performed using the computational fluid dynamic (CFD) tool to solve 3D Navier-Stokes equations with the species transport equations. The efficiency of mixing is estimated by the calculation of the mixing index for different cases of Reynolds number. The geometry of micro Kenics collected with a series of six helical elements twisted 180° and arranged alternately to achieve the higher level of chaotic mixing, inside a pipe with a Y-inlet. Under a wide range of Reynolds numbers between 0.1 to 500 and the carboxymethyl cellulose (CMC) solutions with power-law indices among 1 to 0.49, the micro-Kenics proves high mixing Performances at low and high Reynolds number. Moreover the pressure losses of the shear-thinning fluids for different Reynolds numbers was validated and represented.

This article reports a novel design of a micromixer showing efficient mixing by creating vortex flow in a microchannel. The main microchannel splits and recombines into two sub-channels at a tangential position that facilitates the generation of vortex flow. The height and width of the sub-channels are half the height and width of the main microchannel. The fluid flow and the mixing characteristics of the micromixer were demonstrated by performing numerical and experimental studies at different Reynolds numbers (Re = 2.5≈40). The micromixer was fabricated using a standard soft lithography process. The fluid streams from the subchannels create vortex flow in the main microchannel which increases the interface area. The idea of creating multiple vortex flow zones by repeating the design of vortex T-mixer was successfully shown in mixing enhancement. The design of the micromixer is promising for mixing the fluids in a short length of the microchannel (5.5 mm at Re = 10 and 2.6 mm at Re = 40).

A hybrid heat sink design with microchannels and stepped pin-fins is introduced for the hotspot-targeted thermal management of microprocessors. The thermal and hydraulic performance were assessed n...

During the last couple of decades, there have been rapid developments in analysis, design, and fabrication of micromixers [...]

Three-dimensional numerical investigations of a novel passive micromixer were carried out to analyze the hydrodynamic and thermal behaviors of Nano-Non-Newtonian fluids. Mass and heat transfer characteristics of two heated fluids have been investigated to understand the quantitative and qualitative fluid faction distributions with temperature homogenization. The effect of fluid behavior and different Al2O3 nanoparticles concentrations on the pressure drop and thermal mixing performances were studied for different Reynolds number (from 0.1 to 25). The performance improvement simulation was conducted in intervals of various Nanoparticles concentrations (φ = 0 to 5%) with Power-law index (n) using CFD. The proposed micromixer displayed a mixing energy cost of 50–60 comparable to that achieved for a recent micromixer (2021y) in terms of fluid homogenization. The analysis exhibited that for high nanofluid concentrations, having a strong chaotic flow enhances significantly the hydrodynamic and thermal performances for all Reynolds numbers. The visualization of vortex core region of mass fraction and path lines presents that the proposed design exhibits a rapid thermal mixing rate that tends to 0.99%, and a mass fraction mixing rate of more than 0.93% with very low pressure losses, thus the proposed micromixer can be utilized to enhance homogenization in different Nano-Non-Newtonian mechanism with minimum energy.

Optimum configuration of a micromixer with two-layer crossing microstructure was performed using mixing analysis, surrogate modeling, along with an optimization algorithm. Mixing performance was used to determine the optimum designs at Reynolds number 40. A surrogate modeling method based on a radial basis neural network (RBNN) was used to approximate the value of the objective function. The optimization study was carried out with three design variables, viz., the ratio of the main channel thickness to the pitch length (H/PI), the ratio of the thickness of the diagonal channel to the pitch length (W/PI), and the ratio of the depth of the channel to the pitch length (d/PI). Through a primary parametric study, the design space was constrained. The design points surrounded by the design constraints were chosen using a well-known technique called Latin hypercube sampling (LHS). The optimal design confirmed a 32.0% enhancement of the mixing index as compared to the reference design.

Micromixers are classified into two types: active and passive micromixers. Active micromixers promote mixing using moving parts or some external agitation/energy to stir the fluids. Magnetic energy, electrical energy, pressure disturbance, and ultrasonic are examples of the external energies to enhance mixing. Passive micromixers use geometrical modification to cause chaotic advection or lamination to promote the mixing of the fluid samples, and allow easy fabrication and integration with lab-on-a-chip and μ-TAS. In this chapter, both active and passive micromixers are discussed, but the major emphasis is laid on passive micromixer designs and mechanisms. Extensive referencing on active and passive micromixers is not possible due to the limited length of the book, but the diversity of micromixers is introduced as much as possible.

Flow instability and its correlations with performance characteristics were investigated for a centrifugal pump with a volute. Unsteady three-dimensional Reynolds-averaged Navier–Stokes analysis was performed to analyze the flow and performance characteristics using the shear stress transport (SST) turbulence model. The grid dependence and temporal resolution were tested to evaluate the numerical uncertainties, and the numerical solutions were validated using experimental data. The total-to-static head coefficient, the impeller's total-to-static head coefficient, and the volute static pressure recovery coefficient were selected as performance parameters. To identify the flow instability, pressure fluctuations were monitored upstream of the impeller, at the volute inlet, and on the shroud wall of the impeller. Three different types of flow instability were detected in partial-load conditions: inside the volute, upstream of the impeller, and at the interface between the impeller and volute. The time-dependent flow structures were investigated to obtain insight into the onset of the flow instability. The correlation of the onset of the flow instability with the performance curves was discussed.

Multi-objective design optimization was applied to the impeller and volute of a centrifugal pump using surrogate-based optimization techniques and three-dimensional Reynolds-averaged Navier–Stokes (RANS) analysis. The objective functions used to improve the hydraulic performance and operating stability of the pump were the hydraulic efficiency at the design condition and the flow rate at which the maximum volute pressure recovery coefficient occurs. Three design variables were selected based on the results of a sensitivity analysis: the blade outlet angle, the constants in determining the impeller outlet width, and the cross-sectional area of the volute. Using response surface approximation (RSA), surrogate models were constructed for the objective functions based on numerical results at experimental points obtained by Latin hypercube sampling (LHS). The representative Pareto-optimal solutions obtained by the multi-objective genetic algorithm (MOGA) show enhanced objective function values compared to the baseline design. The results of unsteady calculation show that the flow instability of the centrifugal pump was successfully suppressed by the optimization.

In the present study, a multi-objective optimization of a flow straightener in a firefighting water cannon is performed by using the surrogate modeling and a hybrid multi-objective genetic algorithm to increase the jet range of the water cannon. Based on analysis using the three-dimensional Reynolds-averaged Navier-Stokes equations, the optimization is carried with a surrogate model and the radial basis neural network. Three geometric design variables, i.e., the length, the thickness of the blade, and the radius of the outer pipe of the flow straightener, are selected for the optimization. The pressure drop through the water cannon and the area-averaged turbulent kinetic energy at the outlet of the water cannon, which are closely related to the jet range of the water cannon, are selected as the objective functions to be minimized. The design space is determined through a parametric study, and the Latin hypercube sampling method is used to select the design points in the design space. The Pareto-optimal solutions are obtained through the optimization. Five representative Pareto-optimal solutions are selected to study the trade-off between two objectives.

A wide range of existing passive micromixers are reviewed, and quantitative analyses of ten typical passive micromixers were performed to compare their mixing indices, pressure drops, and mixing costs under the same axial length and flow conditions across a wide Reynolds number range of 0.01–120. The tested micromixers were selected from five types of micromixer designs. The analyses of flow and mixing were performed using continuity, Navier-Stokes and convection-diffusion equations. The results of the comparative analysis were presented for three different Reynolds number ranges: low-Re (Re ≤ 1), intermediate-Re (1 < Re ≤ 40), and high-Re (Re > 40) ranges, where the mixing mechanisms are different. The results show a two-dimensional micromixer of Tesla structure is recommended in the intermediate- and high-Re ranges, while two three-dimensional micromixers with two layers are recommended in the low-Re range due to their excellent mixing performance.

The performance of double-layer microchannel heat sinks are evaluated comparatively for the parallel flow, counter flow, and transverse flow configurations with and without hotspots as heating cond...

A numerical investigation of a fluidic oscillator was performed to understand the unsteady internal flow field and geometrical effects on the performance using three-dimensional unsteady Reynolds-averaged Navier-Stokes equations. Effects of the two geometrical parameters, i.e., the inlet width of the mixing chamber and outlet throat width, on peak jet velocity ratio at the exit and pressure drop through the oscillator, were evaluated. The unsteady simulation was performed using shear stress transport turbulence model with air as working fluid at Reynolds number 30000. Computational results showed good qualitative and quantitative agreements with available experimental results for the flow structure and frequency of the oscillating jet. Results of the parametric study suggested that the inlet width affected significantly the flow in the fluidic oscillator, while effects of the throat width on the performance parameters were not remarkable.

The bobsleigh bumper shape was optimized to reduce aerodynamic drag using three-dimensional Reynolds-averaged Navier–Stokes analysis and surrogate modeling. The k–ω shear stress transport turbulence model was used as turbulence closure. The numerical results for the drag coefficient of the bobsleigh showed reasonable agreements with the experimental data. On the basis of the results of a parametric study using six parameters related to the shape of the front and rear bumpers, three parameters, i.e., the distances between the bumpers and the ground and the leading angle of the front bumper, were selected as design variables, and the drag coefficient was employed as an objective function for optimization. Latin hypercube sampling was used to select twenty-five design points in the design space. A surrogate model of the objective function was constructed using response surface approximation. The aerodynamic drag of the bobsleigh was reduced by 3.08% with the optimization compared with the reference design.

A performance analysis and three-objective design optimization were performed for the staggered partial diffuser vanes in a centrifugal pump using three-dimensional Reynolds-averaged Navier–Stokes equations. First, the performance of the diffuser vanes was evaluated for four different arrangements: full-height diffuser vanes, vaneless diffuser, half vanes attached to the hub, half vanes attached to the shroud, and staggered vanes attached alternately to the hub and the shroud. The staggered partial diffuser vanes were optimized using the following design variables: the installation angle of the vanes, the heights of the vanes attached to the hub and shroud, and the angle of rotation of the straight part on the pressure surface of the vanes. The objective functions were the hydraulic efficiency, the flowrate of the maximum pressure recovery, and the operating range of the diffuser. The Kriging model was used to construct surrogate models of the objective functions based on the results at the design points obtained by Latin hypercube sampling. The Pareto-optimal solutions were obtained by a multi-objective genetic algorithm (MOGA). The representative Pareto-optimal solutions for the staggered diffuser vanes obtained by the K-means clustering showed the improved performances in terms of both the hydraulic performance and operating range compared with the full-height diffuser vanes and the baseline design.

The effects of the cross-sectional area of a volute on suction recirculation and cavitation in a centrifugal pump were investigated. The pump performance and fluid flow were analyzed using both steady and unsteady three-dimensional Reynolds-averaged Navier–Stokes analyses. The shear stress transport (SST) model was adopted as a turbulence closure model, and a simplified Rayleigh–Plesset cavitation model and a homogeneous two-phase mixture model were used to simulate the cavitating flow inside the pump. A constant to determine the designed circumferential velocity of the volute was selected as the geometric parameter for a parametric study. The hydraulic efficiency, head coefficient, blockage in front of the impeller, and critical cavitation number for a head-drop of 3% were selected as the performance parameters to evaluate the hydraulic performance. The results show that unlike the blockage, the hydraulic and suction performances were affected significantly by the volute shape. Both steady and unsteady flow analyses showed that the onset and development of suction recirculation were relatively unaffected by the volute geometry and the best efficiency point of the pump.

The present work proposes a planar micromixer design comprising hybrid mixing modules of split-and-recombine units and curved channels with radial baffles. The mixing performance was evaluated numerically by solving the continuity and momentum equations along with the advection-diffusion equation in a Reynolds number range of 0.1&ndash, 80. The variance of the concentration of the mixed species was considered to quantify the mixing index. The micromixer showed far better mixing performance over whole Reynolds number range than an earlier split-and-recombine micromixer. The mixer achieved mixing indices greater than 90% at Re &ge, 20 and a mixing index of 99.8% at Re = 80. The response of the mixing quality to the change of three geometrical parameters was also studied. A mixing index over 80% was achieved within 63% of the full length at Re = 20.

A laminar flow micro fuel cell comprising of bridge-shaped microchannel is investigated to find out the effects of the cross-section shape of the microchannel on the performance. A parametric study is performed by varying the heights and widths of the channel and bridge shape. Nine different microchannel cross-section shapes are evaluated to find effective microchannel cross-sections by combining three bridge shapes with three channel shapes. A three-dimensional fully coupled numerical model is used to calculate the fuel cell&rsquo, s performance. Navier-Stokes, convection and diffusion, and Butler-Volmer equations are implemented using the numerical model. A narrow channel with a wide bridge shape shows the best performance among the tested nine cross-sectional shapes, which is increased by about 78% compared to the square channel with the square bridge shape.

The effects of a rotor–stator interface model on the hydraulic and suction performance of a single-stage centrifugal pump have been evaluated. A three-dimensional Reynolds-averaged Navier–Stokes (RANS) analysis was performed using the shear-stress transport turbulence model. The cavitating flow was simulated using a homogeneous two-phase mixture model and a simplified Rayleigh–Plesset cavitation model. Three performance parameters were selected to compare different cases: the hydraulic efficiency, head coefficient, and critical cavitation number for a head-drop of 3%. Frozen-rotor and stage models were evaluated for the rotor–stator interface. The evaluation was done using three different computational domains: one with a single passage of the impeller with a vaneless diffuser, one with a single passage of the impeller with the whole shape of volute casing, and another with the whole passage of the impeller with the whole shape of volute casing. Two different volute shapes were also tested. The results show that it is desirable to use the whole domain of the impeller and volute with the frozen-rotor model for accurate prediction of the suction performance. The stage model is not recommended for the prediction of the suction performance of the centrifugal pump with the volute in severe off-design conditions.

In this work, a comparative investigation of chaotic flow behavior inside multi-layer crossing channels was numerically carried out to select suitable micromixers. New micromixers were proposed and compared with an efficient passive mixer called a Two-Layer Crossing Channel Micromixer (TLCCM), which was investigated recently. The computational evaluation was a concern to the mixing enhancement and kinematic measurements, such as vorticity, deformation, stretching, and folding rates for various low Reynolds number regimes. The 3D continuity, momentum, and species transport equations were solved by a Fluent ANSYS CFD code. For various cases of fluid regimes (0.1 to 25 values of Reynolds number), the new configuration displayed a mixing enhancement of 40%–60% relative to that obtained in the older TLCCM in terms of kinematic measurement, which was studied recently. The results revealed that all proposed micromixers have a strong secondary flow, which significantly enhances the fluid kinematic performances at low Reynolds numbers. The visualization of mass fraction and path-lines presents that the TLCCM configuration is inefficient at low Reynolds numbers, while the new designs exhibit rapid mixing with lower pressure losses. Thus, it can be used to enhance the homogenization in several microfluidic systems.

A numerical study was performed to evaluate the thermal-hydraulic performance of a finger type cooling module, where multiple jets impinge on the surface with concave dimples, in the divertor of a nuclear fusion reactor. Conjugate heat transfer was analyzed in both the solid and fluid domains using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. The computational domain consisted of a single fluid domain and three solid domains: tile, thimble, and cartridge. The numerical results for the temperature variation on the tile were validated in comparison with the experimental data. A parametric study was performed with two design variables, the ratios of dimple diameter and dimple height to the nozzle diameter, and two dimple arrays (inline and staggered arrays). The parametric study showed that the heat transfer rate was increased by up to 2.62% by introducing concave dimples, and that the heat transfer and pressure drop performances increased with increasing diameter and height of the dimples for a specified dimple array.

Microchannel heat sinks with ribbed channels in various configurations have been analyzed numerically using the three-dimensional Navier–Stokes equations. Six configurations of ribbed microchannels (i.e., rectangular, semicircular, triangular, rectangular–triangular, rectangular–semicircular, and triangular–circular) were tested with a fixed width and length of ribs, and compared to smooth channels in a Reynolds number range of 100–500. The results indicate that thermal resistance of microchannels is greatly reduced by introducing ribs and that triangular ribs show the lowest thermal resistance throughout the Reynolds number range. However, the pressure drop is also increased greatly because of the ribs, and rectangular ribs induced the largest pressure drop.

Design optimization of a backward-curved blades centrifugal pump with specific speed of 150 has been performed to improve hydraulic performance of the pump using surrogate modeling and three-dimensional steady Reynolds-averaged Navier-Stokes analysis. The shear stress transport model was used for the analysis of turbulence. Four geometric variables defining the blade hub inlet angle, hub contours, blade outlet angle, and blade angle profile of impeller were selected as design variables, and total efficiency of the pump at design flow rate was set as the objective function for the optimization. Thirty-six design points were chosen using the Latin hypercube sampling, and three different surrogate models were constructed using the objective function values calculated at these design points. The optimal point was searched from the constructed surrogate model by using sequential quadratic programming. The optimum designs of the centrifugal pump predicted by the surrogate models show considerable increases in efficiency compared to a reference design. Performance of the best optimum design was validated compared to experimental data for total efficiency and head.

Optimization of a centrifugal pump with double volute was performed using surrogate modeling and a multi-objective genetic algorithm to minimize the radial thrust at off-design conditions with minimal loss in hydraulic efficiency. Both steady and unsteady numerical analyses were conducted using three-dimensional Reynolds-averaged Navier–Stokes equations with a shear stress transport turbulent model. The three objective functions are hydraulic efficiency at the design flow rate, and radial thrust coefficient at 70% and 120% of the design flow rate. In addition, three geometric parameters related to the surface curve and the locations of both ends of the rib structure were selected as the design variables for optimization. The Latin hypercube sampling method was used to choose the design points in the design space. The three objective functions were approximated using response surface approximation models. Pareto-optimal solutions representing the trade-off between the objective functions were obtained using a genetic algorithm. Representative optimal designs show that the optimized double volutes significantly reduce both the radial force and the amplitude of the radial force fluctuation with small loss in hydraulic efficiency.

A multi-objective optimization was performed to simultaneously enhance the aerodynamic and aeroacoustic performance of a side channel-type regenerative blower. The aerodynamic characteristics of the regenerative blower were investigated numerically using threedimensional steady and unsteady Reynolds-averaged Navier-Stokes analysis with a shear stress transport turbulence model. On the basis of the aerodynamic sources extracted from the unsteady flow calculation, three-dimensional aeroacoustic analysis was implemented using a finite/infinite element method by solving the variational formulation of Lighthill’s analogy. Three design variables, viz., the ratio of blade height to impeller diameter, ratio of blade width to impeller diameter, and angle between inlet and outlet port, were selected as design variables, and the efficiency and sound pressure level at the design point of the blower were selected as objective functions for the optimization. These two objective functions were estimated numerically through three-dimensional aerodynamic and aeroacoustic analyses at the design points sampled by Latin hypercube sampling in the design space. Pareto-optimal solutions were obtained using a hybrid multi-objective evolutionary algorithm coupled with radial basis neural network models as surrogates of the objective functions. Three arbitrarily selected optimum designs of the regenerative blower show significant increases in efficiency and reductions in sound pressure level compared to a reference design.

Micromixers are important components of microfluidic systems [...].

Vortex flow increases the interface area of fluid streams by stretching along with providing continuous stirring action to the fluids in micromixers. In this study, experimental and numerical analyses on a design of micromixer that creates vortex flow were carried out, and the mixing performance was compared with a simple micro T-mixer. In the vortex micro T-mixer, the height of the inlet channels is half of the height of the main mixing channel. The inlet channel connects to the main mixing channel (micromixer) at the one end at an offset position in a fashion that creates vortex flow. In the simple micro T-mixer, the height of the inlet channels is equal to the height of the channel after connection (main mixing channel). Mixing of fluids and flow field have been analyzed for Reynolds numbers in a range from 1–80. The study has been further extended to planar serpentine microchannels, which were combined with a simple and a vortex T-junction, to evaluate and verify their mixing performances. The mixing performance of the vortex T-mixer is higher than the simple T-mixer and significantly increases with the Reynolds number. The design is promising for efficiently increasing mixing simply at the T-junction and can be applied to all micromixers.

This work presents a three-objective design optimization of a centrifugal pump impeller to reduce flow recirculation and cavitation using three-dimensional (3D) Reynolds-averaged Navier–Stokes equations. A cavitation model was used to simulate the multiphase cavitating flow inside the centrifugal pump. The numerical results were validated by comparing them with experimental data for the total head coefficient and critical cavitation number. To achieve the optimization goals, blockage at 50% of the design flow rate, hydraulic efficiency at the design flow rate, and critical cavitation number for a head-drop of 3% at 125% of the design flow rate were selected as the objective functions. Based on the results of the elementary effect (EE) method, the design variables selected were the axial length of the blade, the control point for the meridional profile of the shroud, the inlet radius of the blade hub, and the incidence angle of tip of the blade. Kriging models were constructed to approximate the objective functions in the design space using the objective function values calculated at the design points selected by Latin hypercube sampling (LHS). Pareto-optimal solutions were obtained using a multi-objective genetic algorithm (MOGA). Six representative Pareto-optimal designs (POD) were analyzed to evaluate the optimization results. The PODs showed large improvements in the objective functions compared to the baseline design. Thus, both the hydraulic performance and the reliability of the centrifugal pump were improved by the optimization.