A Concave Impeller Design Improves Centrifugal Pump Performance: A CFD-Based Comparative Review

Centrifugal pumps remain among the most widely used fluid transportation systems across industrial, agricultural, and domestic applications because of their simple construction, operational reliability, and cost-effectiveness. Since the impeller is the primary component responsible for transferring mechanical energy to the working fluid, optimizing its geometry has become an important research direction for improving hydraulic performance. The reviewed study investigates whether modifying the blade geometry of a semi-open impeller into concave and convex configurations can enhance pump performance compared with the conventional design. Using Computational Fluid Dynamics (CFD) simulations performed in SolidWorks Flow Simulation, the researchers evaluated pressure distribution, volumetric flow rate, and hydraulic efficiency. This review summarizes the study's objectives, methodology, principal findings, scientific contributions, and practical significance for centrifugal pump design and engineering applications.

Bibliographic Information

Item	Information
Article Title	A concave impeller: A new modified semi-open impeller for higher performance of centrifugal pumps
Authors	Rahmat Azis Nabawi; Egi Fadillah; Haris Shiddiq Mulyadi; Muhammad Shadiq Fahrezi; Firza Fernanda Putra
Journal	Journal of Engineering Researcher and Lecturer
Volume	4
Issue	1
Publication Year	2025
Pages	22–30
DOI	https://doi.org/10.58712/jerel.v4i1.178
Publisher	Researcher and Lecturer Society
License	Creative Commons Attribution 4.0 International (CC BY 4.0)
ISSN	2963-7511
Keywords	centrifugal pump; impeller design; CFD simulation; pressure distribution; volume flow rate; semi-open impeller

Highlights

Introduces a novel concave semi-open impeller as an alternative to the conventional flat-blade impeller.
Compares three impeller geometries—original, concave, and convex—using Computational Fluid Dynamics (CFD) simulation.
Evaluates pump performance based on outlet pressure, pressure distribution, volumetric flow rate, torque, and hydraulic efficiency.
Demonstrates that the concave impeller produces the highest outlet pressure and the greatest hydraulic efficiency among the evaluated designs.
Shows that improved blade geometry can reduce unfavorable flow interaction inside the pump casing and improve flow trajectories.
Provides practical engineering evidence that relatively simple geometric modifications can significantly improve centrifugal pump performance without changing the overall pump configuration.

1. Research Background

Centrifugal pumps play an essential role in numerous engineering applications because they provide reliable fluid transportation with relatively simple construction and economical operating costs. Their extensive use in industrial processing, water distribution, agriculture, and domestic systems has encouraged continuous efforts to improve hydraulic efficiency and operational performance. Since the impeller is the component responsible for transferring rotational energy into fluid pressure, its geometry strongly influences pressure generation, flow characteristics, and overall pump efficiency.

Previous investigations have primarily focused on optimizing centrifugal pump performance by modifying blade outlet angles, blade inclination, and the number of impeller blades. These design variables have been shown to influence pressure generation, power consumption, and hydraulic efficiency. Nevertheless, comparatively little attention has been given to modifying the three-dimensional blade profile itself while maintaining the general semi-open impeller configuration.

The reviewed study addresses this research gap by proposing two alternative semi-open impeller geometries featuring concave and convex blade profiles. Rather than changing blade quantity or outlet angle, the research evaluates whether altering blade curvature can improve internal pressure distribution, reduce undesirable flow interactions, and enhance hydraulic efficiency. Through Computational Fluid Dynamics (CFD) simulations, the study provides a systematic comparison between the conventional impeller and two newly developed blade geometries under identical operating conditions.

2. Research Objective

To develop new semi-open centrifugal pump impeller designs using concave and convex blade geometries.
To compare the hydraulic performance of the modified impellers with the original semi-open impeller configuration.
To investigate the influence of blade geometry on pressure distribution inside the centrifugal pump.
To evaluate differences in volumetric flow rate at the pump inlet and outlet for each impeller configuration.
To determine the hydraulic efficiency of each impeller using Computational Fluid Dynamics (CFD) simulation.
To identify which impeller geometry provides the highest overall performance for centrifugal pump applications.
To provide engineering insight into how blade shape modification affects internal flow behavior and pump efficiency.

3. Why This Research Matters

Introduces an innovative impeller geometry that expands conventional centrifugal pump design approaches beyond blade angle and blade number optimization.
Demonstrates how Computational Fluid Dynamics (CFD) can accelerate pump development while reducing the need for repeated physical prototyping.
Shows that relatively simple modifications to blade geometry can substantially improve hydraulic efficiency.
Provides practical design guidance for engineers seeking higher pump performance without redesigning the entire pump assembly.
Improves understanding of how pressure distribution and internal flow trajectories influence centrifugal pump efficiency.
Supports the development of more energy-efficient pumping systems capable of reducing long-term operational costs.
Creates a foundation for future optimization studies involving blade curvature, blade number, rotational speed, and alternative working fluids.

4. Research Methodology

The study employed a quantitative engineering approach based entirely on Computational Fluid Dynamics (CFD) simulation to evaluate the hydraulic performance of three semi-open centrifugal pump impeller designs. Instead of manufacturing physical prototypes, the researchers developed digital models of the original impeller together with two newly proposed blade geometries—concave and convex—and compared their hydraulic characteristics under identical operating conditions using SolidWorks Flow Simulation (Research License 2021).

Research Design

Simulation-based engineering design and performance evaluation.
Comparative analysis of three semi-open impeller geometries.
Numerical fluid-flow analysis using Computational Fluid Dynamics (CFD).
Hydraulic performance assessment based on pressure, volumetric flow rate, torque, pressure drop, and efficiency.

Impeller Configurations

Three centrifugal pump impeller models were evaluated throughout the study:

Original semi-open impeller.
Modified semi-open impeller with a concave blade profile.
Modified semi-open impeller with a convex blade profile.

Each impeller was installed within the same pump casing so that the influence of blade geometry could be isolated without introducing additional structural variables.

Simulation Parameters

Simulation software: SolidWorks Flow Simulation (Research License 2021).
Analysis type: Internal flow analysis.
Working fluid: Water.
Impeller rotational speed: 5000 RPM (523.6 rad/s).
Boundary condition: Environment pressure applied at both inlet and outlet.
Wall condition: Default wall condition.
Initial condition: Default initial condition.

Mesh Configuration

The CFD model employed a combination of global and local mesh refinement to improve numerical accuracy while maintaining computational efficiency. A global mesh level of 5 was selected based on previous studies indicating that this level provides simulation accuracy comparable to finer mesh levels with substantially lower computational cost. Additional local mesh refinement was applied around the impeller surfaces where fluid interaction was most significant. Each simulation model contained approximately two million computational cells.

Simulation Procedure

A rotating fluid region was assigned around the impeller using the Local Region Sliding approach. The rotating region operated at a constant speed of 5000 RPM to represent actual pump operating conditions. Pressure and volumetric flow rate were monitored at both the inlet and outlet boundaries, while torque acting on the impeller was determined using the surface goal function available in the simulation software.

Hydraulic efficiency was subsequently calculated from the simulated pressure drop, inlet volumetric flow rate, impeller rotational speed, and generated torque. In addition to numerical values, contour plots of pressure distribution and flow trajectories were analyzed to interpret internal flow behaviour for each impeller configuration.

Performance Indicators

Pressure at pump inlet.
Pressure at pump outlet.
Pressure distribution inside the pump casing.
Pressure drop.
Volumetric flow rate at inlet.
Volumetric flow rate at outlet.
Torque acting on the impeller.
Hydraulic efficiency.
Flow trajectory and pressure contour visualization.

5. Key Findings

The Concave Impeller Produced the Highest Outlet Pressure

All three impeller configurations generated an identical inlet pressure of 0.10 MPa. However, the modified concave impeller produced the highest outlet pressure of 0.32 MPa, whereas both the original and convex impellers generated outlet pressures of 0.30 MPa. This result indicates that the concave blade geometry transfers mechanical energy to the working fluid more effectively than the alternative designs.

The Highest Outlet Flow Rate Was Achieved by the Concave Impeller

The CFD simulations revealed noticeable differences in volumetric flow rate among the three impeller configurations. Although the convex impeller produced the highest inlet flow rate, the concave impeller achieved the greatest outlet flow rate. Unlike the convex impeller, which exhibited nearly identical inlet and outlet flow rates, both the original and concave impellers showed increased flow rates toward the outlet, suggesting more effective energy conversion inside the pump.

Hydraulic Efficiency Improved Significantly

Among the evaluated designs, the concave impeller demonstrated the highest hydraulic efficiency at 32%. The conventional impeller achieved an efficiency of 27%, while the convex impeller recorded the lowest efficiency at 26%. These findings indicate that modifying blade curvature into a concave profile can substantially improve pump performance under the simulated operating conditions.

Pressure Distribution Became More Favorable

Pressure contour analysis demonstrated that the maximum pressure generated by the concave impeller was concentrated near the outlet channel, facilitating smoother fluid discharge from the pump. In contrast, the original and convex impellers produced different pressure distributions, with the original design exhibiting greater pressure concentration along the pump casing wall.

Improved Internal Flow Trajectories

Flow trajectory visualization showed that the concave impeller directed the working fluid more efficiently toward the outlet while reducing unnecessary interaction between the fluid and the pump casing. The original impeller exhibited flow separation and collisions that contributed to pressure losses, whereas the convex impeller generated comparatively lower pressure because of its blade geometry.

Blade Geometry Strongly Influenced Pump Performance

The comparative analysis confirms that changing blade curvature alone can significantly alter internal flow characteristics, pressure distribution, volumetric flow rate, and hydraulic efficiency. Among the three investigated geometries, the concave blade profile consistently provided the best overall hydraulic performance.

6. Scientific Contribution

Introduces a novel concave semi-open impeller geometry as an alternative to conventional centrifugal pump blade designs.
Demonstrates that blade curvature alone can significantly improve hydraulic efficiency without altering the overall pump configuration.
Provides a systematic CFD-based comparison between original, concave, and convex semi-open impeller geometries under identical operating conditions.
Expands current centrifugal pump optimization strategies beyond traditional blade-angle and blade-number modifications.
Explains how blade geometry influences pressure distribution and internal flow trajectories using contour visualization.
Provides engineering evidence that improved internal flow behaviour directly contributes to higher outlet pressure and increased hydraulic efficiency.
Offers a practical numerical methodology that can support future centrifugal pump optimization studies before physical prototype fabrication.

7. Industrial Implications

Supports the development of higher-efficiency centrifugal pumps for industrial fluid transportation systems.
Provides an engineering solution that may reduce operational energy consumption through improved hydraulic performance.
Demonstrates how CFD simulation can shorten product development cycles by evaluating alternative impeller geometries before manufacturing.
Offers practical guidance for pump manufacturers seeking performance improvements through relatively simple blade redesign.
May contribute to lower maintenance requirements by improving internal flow characteristics and reducing unfavorable pressure losses.
Applicable to industrial sectors relying on centrifugal pumps, including manufacturing, agriculture, water supply, chemical processing, and energy systems.
Provides a foundation for future commercial development of high-performance semi-open impellers with improved hydraulic characteristics.

8. Research Limitations

The investigation relied entirely on Computational Fluid Dynamics (CFD) simulations without experimental validation using a physical pump prototype.
Only three impeller geometries—original, concave, and convex—were evaluated, while additional blade profiles were beyond the scope of the study.
The simulations were conducted under a single rotational speed of 5000 RPM, and different operating conditions were not investigated.
Water was used as the only working fluid; pump performance with fluids of different physical properties remains unknown.
The study focused primarily on hydraulic characteristics and did not examine manufacturing feasibility, production cost, structural durability, or long-term operational reliability.
Potential influences of cavitation, vibration, and experimental uncertainties were not evaluated within the numerical investigation.

9. Future Research Opportunities

Conduct experimental validation by fabricating prototype impellers and comparing laboratory measurements with the Computational Fluid Dynamics (CFD) simulation results.
Investigate the hydraulic performance of concave impellers under various rotational speeds to evaluate their effectiveness across a wider operating range.
Examine the influence of different blade numbers in combination with the proposed concave blade geometry to identify the optimal impeller configuration.
Evaluate the performance of the modified impellers using fluids with different physical properties, including higher viscosity or multiphase flow conditions.
Perform cavitation analysis to determine how the concave blade geometry affects cavitation resistance and pump reliability during demanding operating conditions.
Optimize additional geometric parameters such as blade thickness, blade curvature, outlet angle, inlet angle, and impeller diameter using numerical optimization techniques.
Investigate transient flow behavior, turbulence characteristics, and unsteady pressure fluctuations that were beyond the scope of the present steady-state simulation.
Combine CFD simulation with optimization algorithms or artificial intelligence techniques to automatically identify high-performance impeller geometries.
Study structural integrity, mechanical stress distribution, and fatigue performance of the proposed impeller design under long-term operating conditions.
Evaluate the economic feasibility, manufacturing complexity, and life-cycle performance of the concave impeller for large-scale industrial implementation.

10. Potential for Public Policy Citation

Although this study primarily focuses on centrifugal pump engineering, its findings have broader relevance for policies promoting industrial energy efficiency, sustainable manufacturing, and engineering innovation. Improvements in hydraulic efficiency can contribute to reducing electricity consumption in pumping systems, which are widely used in water supply, industrial processing, agriculture, and public infrastructure.

The research also demonstrates the value of simulation-driven engineering design as a cost-effective approach for accelerating technological innovation while minimizing prototype development costs. Such methodologies support national initiatives encouraging digital engineering, advanced manufacturing, and environmentally sustainable industrial technologies.

Consequently, this study may serve as a useful technical reference for engineering researchers, industrial designers, technology development agencies, standards organizations, and policymakers involved in promoting energy-efficient pumping systems and sustainable industrial development.

11. Who Should Read This Paper?

Mechanical engineers specializing in fluid machinery and centrifugal pump design.
Researchers working in Computational Fluid Dynamics (CFD) and numerical fluid-flow simulation.
Industrial engineers responsible for improving pump efficiency and reducing operational energy consumption.
Graduate students studying turbomachinery, hydraulic engineering, and mechanical design.
Pump manufacturers seeking practical approaches to improve hydraulic performance through blade redesign.
Researchers investigating impeller optimization and internal flow characteristics.
Professionals involved in industrial fluid transportation, water supply systems, agricultural irrigation, and process engineering.
Engineering educators teaching fluid mechanics, turbomachinery, computational simulation, and pump engineering.

12. Frequently Asked Questions (FAQ)

What is the primary objective of this research?

The study aims to determine whether modifying the blade geometry of a semi-open centrifugal pump impeller into concave and convex profiles can improve hydraulic performance compared with the conventional impeller design using Computational Fluid Dynamics (CFD) simulations.

Why was a concave impeller introduced?

The concave blade geometry was proposed to improve pressure generation, optimize internal flow trajectories, reduce unfavorable fluid interaction inside the pump casing, and ultimately increase hydraulic efficiency without changing the overall pump configuration.

Which simulation software was used?

The researchers performed all numerical analyses using SolidWorks Flow Simulation (Research License 2021), employing the Computational Fluid Dynamics (CFD) method to evaluate pump performance.

Which impeller produced the best overall performance?

Among the three evaluated configurations, the concave impeller demonstrated the best overall hydraulic performance by producing the highest outlet pressure, the highest outlet volumetric flow rate, and the greatest hydraulic efficiency.

How much efficiency improvement was achieved?

According to the simulation results, the concave impeller achieved a hydraulic efficiency of 32%, compared with 27% for the original impeller and 26% for the convex impeller.

Why is pressure distribution important in centrifugal pumps?

Pressure distribution reflects how effectively mechanical energy is transferred from the rotating impeller to the working fluid. A more favorable pressure distribution generally leads to smoother flow, reduced hydraulic losses, and improved pump efficiency.

Was the proposed impeller experimentally tested?

No. The study was based entirely on Computational Fluid Dynamics (CFD) simulations. Experimental fabrication and laboratory validation were recommended as future work.

Can the proposed impeller be applied directly in industry?

The simulation results indicate promising performance improvements. However, prototype manufacturing, experimental testing, durability evaluation, and economic assessment should be completed before large-scale industrial implementation.

13. Suggested Citations

UNP–Teknomekanik Style

R. A. Nabawi, E. Fadillah, H. S. Mulyadi, M. S. Fahrezi, and F. F. Putra, "A concave impeller: A new modified semi-open impeller for higher performance of centrifugal pumps," Journal of Engineering Researcher and Lecturer, vol. 4, no. 1, pp. 22–30, 2025. https://doi.org/10.58712/jerel.v4i1.178.

APA 7th Edition

Nabawi, R. A., Fadillah, E., Mulyadi, H. S., Fahrezi, M. S., & Putra, F. F. (2025). A concave impeller: A new modified semi-open impeller for higher performance of centrifugal pumps. Journal of Engineering Researcher and Lecturer, 4(1), 22–30. https://doi.org/10.58712/jerel.v4i1.178

IEEE

Harvard

Nabawi, R.A., Fadillah, E., Mulyadi, H.S., Fahrezi, M.S. and Putra, F.F. (2025) 'A concave impeller: A new modified semi-open impeller for higher performance of centrifugal pumps', Journal of Engineering Researcher and Lecturer, 4(1), pp. 22–30. doi:10.58712/jerel.v4i1.178.

Vancouver

Nabawi RA, Fadillah E, Mulyadi HS, Fahrezi MS, Putra FF. A concave impeller: A new modified semi-open impeller for higher performance of centrifugal pumps. Journal of Engineering Researcher and Lecturer. 2025;4(1):22–30. doi:10.58712/jerel.v4i1.178.

Chicago Author–Date

Nabawi, Rahmat Azis, Egi Fadillah, Haris Shiddiq Mulyadi, Muhammad Shadiq Fahrezi, and Firza Fernanda Putra. 2025. "A Concave Impeller: A New Modified Semi-Open Impeller for Higher Performance of Centrifugal Pumps." Journal of Engineering Researcher and Lecturer 4 (1): 22–30. https://doi.org/10.58712/jerel.v4i1.178.

MLA 9th Edition

Nabawi, Rahmat Azis, et al. "A Concave Impeller: A New Modified Semi-Open Impeller for Higher Performance of Centrifugal Pumps." Journal of Engineering Researcher and Lecturer, vol. 4, no. 1, 2025, pp. 22–30. Crossref, https://doi.org/10.58712/jerel.v4i1.178.

14. Editorial Note

This review has been prepared exclusively for educational, scientific, and scholarly communication purposes. The analysis presented in this article is derived solely from the published research paper and aims to help readers understand the study's research background, objectives, methodology, principal findings, scientific contributions, and engineering significance in a concise and accessible format.

The review does not replace the original publication. Readers, researchers, engineers, and students are strongly encouraged to access, read, download, and cite the original research article whenever its findings contribute to academic studies, engineering projects, technical reports, or industrial applications. Proper citation ensures appropriate scholarly recognition for the authors and promotes responsible scientific communication.

15. SEO Meta Description

Comprehensive review of a CFD-based study introducing a novel concave semi-open impeller for centrifugal pumps. Learn how blade geometry improves pressure distribution, volumetric flow rate, and hydraulic efficiency compared with conventional impeller designs.

16. SEO Keywords

concave impeller, centrifugal pump, semi-open impeller, impeller design, Computational Fluid Dynamics, CFD simulation, hydraulic efficiency, pressure distribution, volumetric flow rate, pump optimization, pump performance, fluid mechanics, SolidWorks Flow Simulation, turbomachinery, mechanical engineering