Design Of Gear Pump Research Articles

Integrated CFD-FEM approach for external gear pump vibroacoustic field prediction

In this work, a three-dimensional fluid-structural and vibro-acoustics coupled model of a gear pump is presented. Gear pumps represent the majority of the positive displacement machines used for flow generation in fluid power systems. Typically, the dynamics of gear pumps are dependent on the characteristics of the fluid dynamics inside the pump, which translates into vibrations to the housing. These vibrations then propagate to the surrounding medium and emit sound. The purpose of this study is to propose a three-dimensional fully integrated computational model to simulate the complete gear pump behaviour from the fluid dynamics to the structural vibrations, up to the vibroacoustic response. In this hybrid configuration, a transient CFD (Computational Fluid Dynamics) model is first developed to simulate the 3D flow field with a deforming and re-meshing approach to take into account the variation of the volume between the gears. Second, the internal pressure field calculated at each time step is then used as a loading into a structural FEM (Finite Element Method) model of the gear pump to compute the actual stresses and deformations of the housing. Third, the results of the structural response are used as excitation in a vibroacoustic sub-model to simulate the radiated noise using a high-order FEM technique. The comparison between the numerical and experimental flow curves validates the CFD model. The sound power calculations from the vibroacoustic model show good comparison with the sound intensity measurements around the pump casing, confirming the validity of the proposed coupled model. The described CFD-FEM approach proves to be a powerful gear pump design tool: it provides a reliable estimate of gear pump working parameters such as fluid power and vibroacoustic characteristics, starting from the CAD (Computer-Aided Design) geometry of the components. Furthermore, being one of the first multi-domain simulation models of a gear pump, this work can be useful to researchers as a starting point to correlate the noise emitted with the internal flow in full 3D conditions.

Анализ конструктивных и технологических особенностей шестеренчатых насосов

The article presents the main design and technological features of gear pumps with a description of the contacts of the gear wheels during their interaction and manufacturing accuracy. The increase in contacts in the interdental space reduces the pulsation by 75%, the noise level by 5 decibels. The use of helical gears increases the efficiency of gear pumps and reduces pulsation. External gear pump with axial compensation with high precision and high quality materials resistant to fatigue. Internal gear pumps have a compact body and are less noisy. In practice, external gear pumps are most commonly used due to their simple design and low cost. The gear pump housing is subject to wear due to high pressure. During operation of the pump, uneven stresses occur, which leads to fatigue loads on the shaft in one direction. Additional pulsation entails oscillations of the structure. The gear pump’s own vibrations contribute to its failure, especially if the rotation speed is 100,000 cycles. During the operation of a gear pump, noise occurs that can be dampened with silencers or dampers, which increases the price of the pump. The interdental spaces of a gear pump are prone to cavitation during sudden pressure surges, which increases wear. To eliminate wear, pulsation, vibration, noise, a new design of the gear pump is proposed using various types of oils and methods for correcting the shape of the teeth.

Підвищення ефективності робочого циклу паливного шестерного насоса високого тиску за рахунок використання струминного насоса в якості ступеня підкачування

This article analyzes the possibility of increasing the efficiency of the gear pump operating cycle by using a jet pump as a booster stage. The design of gear pumps is performed for one mode, and most often, it is a mode with minimum speed and high consumption relative to rotation speed. For gas turbine engines, this is the take-off mode, in which the aircraft operates for a few minutes of the entire flight cycle. In other modes, the pump capacity is excessive, reaching more than twice the value in some operational conditions. Due to the excess capacity, overflow valves are used to synchronize the operation of the engine and pump. This approach is a classic solution, but it creates additional mechanical losses and, as a result, reduces the efficiency of the operating cycle of the pump. Therefore, there is a need to improve the matching of engine requirements and pump performance. In this article, a solution that can improve the operating cycle of pumping units within the framework of a classical drive box assembly was analyzed. In the introductory section, the generalized flight cycle of a transport aircraft is analyzed. Based on the results, the modes were determined for which the design calculations of the jet pump were performed. First, the relative characteristics of pressure increase and efficiency are considered. The geometric and operational boundary conditions are accepted considering the fuel overflow relative to the generalized flight cycle. The obtained characteristics are used as a basis for selecting the geometric ratio for the modes with the highest pressure and efficiency. Based on these results, the geometric dimensions of the main sections and the value of the pressure increase at the outlet of the jet pump were obtained. Based on the characteristics of the pressure increase behind the jet pump, the relative characteristics of the reduction in power consumption in the gear pump shaft were obtained. Considering the level of overflow and operating time, the use of a jet pump will save about 50% of the energy input. This is a direct improvement in the operating cycle, and the increased pump inlet pressure will also reduce bearing wear, increase cavitation resistance, and reduce wear from cavitation erosion.

Analysis of straight conjugate internal gear pump through numerical modeling and experimental validation

As a medium and low pressure gear machine without automatic compensation structure for axial and radial clearances, the friction pairs in the straight conjugate internal gear pumps (SCIGPs) depend on the fixed small clearances to seal, lubricate and transfer the force. The oil film design of the friction pairs has become an important part of gear pump design. However, there has never been a publicly published research on the oil film design of the SCIGP in past literature. This paper applies orthogonal test to the oil film design of the SCIGP for the first time to determine the best working clearances. With this goal, the paper first provides the mathematical models for analyzing the internal leakage flow and the viscous friction loss, which elucidate the relationships between the leakage and the friction loss with working conditions. After that, the orthogonal test scheme for numerical simulation was designed on the basis of determining the range of oil film thickness. The paper also propounds the viewpoints of using the range-method to estimate the primary and secondary relationship of factors and determining the optimal combination according to the test target. Based on this concept, the main factors affecting the target are procured and the optimal working clearances of the friction pairs are determined. For the purpose of verifying the model, the redesigned prototype was tested and compared with the simulation results. The results validate the applicability of the simulation model and the correctness of the simulation method. Finally, the paper summarizes the ways to improve the total efficiency and the working conditions at the highest efficiency.

The Influence of Radial and Axial Gaps on Volumetric Efficiency of External Gear Pumps

The design of gear pumps and motors is focused on more efficient units which are possible to achieve using advanced numerical simulation techniques. The flow that appears inside the gear pump is very complex, despite the simple design of the pump itself. The identification of fluid flow phenomena in areas inside the pump, considering the entire range of operating parameters, is a major challenge. This paper presents the results of simulation studies of leakages in axial and radial gaps in an external gear pump carried out for different gap shapes and sizes, as well as various operating parameters. To investigate the processes that affect pump efficiency and visualize the fluid flow phenomena during the pump’s operation, a CFD model was built. It allows for a detailed analysis of the impact of the gears’ eccentricity on leakages and pressure build-up on the circumference. Performed simulations made it possible to indicate the relationship between leakages resulting from the axial and radial gap, which has not been presented so far. To verify the CFD model, experimental investigations on the volumetric efficiency of the external gear pump were carried out. Good convergence of results was obtained; therefore, the presented CFD model is a universal tool in the study of flow inside external gear pumps.

Computer Aided Modeling Design of External Gear Pump

In order to solve the problems in the structural design of the gear pump in use, three dimensional modeling software is used to complete the parts modeling of gear pump one by one, it is assembled as a gear pump, and the structure of gear pump is optimized by auxiliary design, further improve the performance of gear pump, Computer aided modeling design can effectively improve the design efficiency, Optimize the structure performance, reduce the design cost and improve the economic benefit.

Finite Element Analysis and Optimization of CBY-100 Gear Pump Body

The research of Gear Pump lightweight can save material and reduce weight on the Premise of meeting performance requirements. Use ANSYS14.0 Software finite element analysis CBY-100 gear Pump body, the Stress and Displacement of QT450-10 material Pump body were analyzed to meet the requirements of strength and rigidity. The same method of analysis, the Stress and Displacement of the Pump body are optimized to determine the optimal structure size which meets the requirements of strength and rigidity; the Stress and Displacement of ZL111 cast aluminum Pump body also meet the requirements of strength and rigidity, complete the lightweight design of gear pump. CAD improves research efficiency, reduces research cost and promotes technological innovation.

Calculation of Unloading Area of Internal Gear Pump and Optimization

In order to obtain the calculation method of the unloading area of the internal gear pump during oil trapping, a pair of internal gears including an external gear and an internal gear was used as the research object to simulate the oil trapping process. The geometric relationship during the meshing process was established, and the unloading area expression was obtained by using the geometric pattern expansion method with the variable f as the independent variable. Guided by a mathematical model, two improved optimization schemes were proposed for the internal gear tooth profile, and the unloading area expressions sud, suda, and sudb were obtained. Taking the meshing gear pair with module 3 and number of teeth 13/19 as examples, the simulation results were very consistent with the existing literature. The reliability of the model and the feasibility of the optimization scheme are obtained based on the theoretical analysis and calculation results. This calculation method of unloading area can be applied to the same type of gear pump design in the future, providing a reference for the design of high pressure and low noise gear pumps.

Optimization of an External Gear Pump using Response Surface Method

ABSTRACTDesign of a new gear pump requires many considerations to get good pump efficiency. In order to achieve optimal results, all parameters must be optimized from the design stage. In this study, ANSYS CFX was used to make parametric analysis in order to optimize a new design of gear pump. Two parameters which are inlet diameter and rotation speed are considered. The response surface method gives an optimum design point for inlet diameter of 15mm and rotation speed of 3500 rev/min. Twin vortices are created in the inlet and the outlet of pump, which strangle the flow. In order to reduce their negative effects on the flow, fillets are created at the inlet and the outlet of the pump.

Numerical and experimental studies on flow performances and hydraulic radial forces of an internal gear pump with a high pressure

Unbalanced radial force is one of the most urgent issues for internal gear pumps (IGPs) working at high working pressures. A numerical model for the prediction of the unbalanced radial force is essential for the structural design of gear pumps, facing the challenges of gear engagement description, dynamic mesh method, and so on. In this work, a three-dimensional computational fluid dynamics model of an IGP with a high working pressure was established based on the 2.5-dimensional dynamic mesh method, with cavitation and gear engagements included. The flow behavior and the hydraulic radial force of the high-pressure IGP were studied, and experiments for pump performances were conducted for comparisons. Results indicated that the numerical model could provide a reasonable solution of the flow rate and pressure pulsation for the high-pressure IGP, verified by the experimental data. The circumferential pressure distribution of the pump does not increase linearly, but presents a stepped increase. The hydraulic radial force fluctuates with gear rotation, and its value increases with the working pressure.

Analysis of continuous-contact helical gear pumps through numerical modeling and experimental validation

Abstract External gear pumps are one of the most commonly used types of positive displacement machines in high pressure hydraulic control systems, fuel-injection and fuel transport systems. Despite many merits of the traditional external gear pump design with involute teeth, the significant flow non-uniformity intrinsic of such design is considered to be a detrimental aspect, since it causes undesired noise emissions and mechanical vibrations. A disruptive concept of continuous-contact helical gear pumps (CCHGP) was proposed and successfully commercialized in the recent past. Such concept was proven to have clear advantages in terms of noise emissions. However, a clear interpretation of the displacing action and the transient features of the delivery flow was never addressed in past literature. This paper addresses this gap by first discussing the family of gear profiles suitable for implementing the CCHGP design. Subsequently, an analysis on the kinematic flow ripple is given, showing how such design concept can reduce or even eliminate the kinematic flow pulsations. The paper also presents a numerical approach for modelling the operation of CCHGPs, starting from the modeling of the geometric features necessary for a fluid dynamic analysis based on a lumped parameter approach. For model validation purposes, a commercial CCHGP was tested at the authors’ research center, and the simulation results were compared against the experiments, to show the level of accuracy of the model, as well as it potentials for future design studies.

Noise Simulation Analysis of a Variable Displacement External Gear Pump and Unloading Groove Optimization

The oil pump is an important part of vehicle engine, whose noise and vibration characteristics affect the engine performance significantly. The noises generat-ed by both the pressure and flow fluctuations are the main contributors to the oil pump noise. In this paper, noise analysis of an external gear pump is carried out by using the computational fluid dynamics (CFD) method and The Lighthill’s acoustic analogy (LAA) algorithm. The fluid pressure and velocity distributions of the flowfield are firstly calculated by using a CFD model. The noises generated by flowfield are simulated and their sound pressure spectra are obtained by using an LAA-based finite element model. By analyzing the phenomenon of oil trapping, the optimum design of unloading groove is put forward, and then the simulation analysis is carried out. According to the finite element model, the noise level of gear pump is reduced and the effect of noise reduction is achieved. The technique presented in this paper can be regarded as a useful tool for optimization design of gear pumps in vehicle engineering.

Theoretical analysis on flow characteristics of melt gear pump

The relationship between Geometric parameters and theoretical flow of melt gear pump is revealed, providing a theoretical basis to melt gear pump design. The paper has an analysis of meshing movement of melt gear pump on the condition of four different tooth numbers, stack movement law and flow ripple. The regulation of flow pulsation coefficient is researched by MATLAB software. The modulus formula of melt gear pump is proposed, consistent with actual situation.

Research Regarding Adaptive Design of Gear Pumps Used for Polymeric Products Engineering

This paper present the results of the researches regarding innovative and adaptive design of gear pumps for engineering of polymeric products with application in production of injection molding machine. It shows the description of gear pump with innovative design and double gear pump – innovative design, highlighting innovative design feature through constructive adaptation depending on requirements, having (30 – 40) % smaller at the axial size, compared to the classic pumps. They highlight the competitive advantages of innovative pumps with superior technological parameters. The paper also shows numerical simulation of technological parameters for pumps in innovative and adaptive variant proving the correctness and the advantages of new variants. Using the innovative variant allows the development a family of gear pumps, single and double, extremely compact, robust, reliable and with low manufacturing costs.

Design and performance analysis of a circular-arc gear pump operating at high pressure and high speed

This paper presents a high-pressure and high-speed gear pump for aerospace application and introduces a circular-arc tooth profile that has no trapping feature and whose gears are in continuous one-point contact in the plane of rotation. Basic dimensions are determined and performance parameters of the gear pump are obtained by structural design of the gear pump. The performance parameters are discussed for different tooth profiles. A disc tool and hob are designed to generate the circular-arc tooth profile. A computer-aided design (CAD) system for the design of the circular-arc gear pump is developed with features of tooth profile design, tool design, and numerical control. The test gears were processed to verify the correctness of CAD system. A study of the outlet pressure of the circular-arc gear pump reveals that the developed high-pressure and high-speed gear pump has low outlet pressure fluctuations.

The Theoretical and Experimental Studies Comparison of the Pressure Pulsation in the Discharge Chamber of the Gear Pump

The paper presents the mathematical model for the additional dynamic force calculation as a result of actuating fluid pressure pulsation in the discharge chamber of the gear pump taking into account the actuating fluid properties for the objective of the gear pump design elements loaded condition specification. The complex of the NSh-32K gear pump experimental studies was carried out, the empirical data allowed to compare theoretical and experimental studies of the pressure pulsation in the discharge chamber of the gear pump. The theoretical and experimental studies comparison reveals that the difference in the pressure fluctuation amplitude values in the discharge chamber of the NSh-32K gear pump does not exceed 14%. Thus, the consideration of the pressure fluctuation amplitude dynamic component in the discharge chamber of the gear pump allows to specify the design elements loaded condition of the gear pump and its operating resource in general.

Fluid-sound coupling simulation and experimental validation for noise characteristics of a variable displacement external gear pump

The oil pump is an important part of vehicle engine, whose noise and vibration characteristics affect the engine performance significantly. The noises generated by both the pressure and flow fluctuations are the main contributors to the oil pump noise. Based on the computational fluid dynamics (CFD) method and the Lighthill’s acoustic analogy (LAA) algorithm, a hybrid simulation technique for noise analysis of an external gear pump, so-called the CFD-LAA method, is presented in this paper. The fluid pressure and velocity distributions of the flow field are firstly calculated by using a CFD model. The noises generated by flow field are simulated and their sound pressure spectra are obtained by using an LAA-based finite element (FE) model. The methodology addresses a numerical noise simulation method which combined the CFD and FE models. Experimental verifications suggest that the CFD-LAA method is effective and feasible for sound field simulation of the external gear pump. Furthermore, the noise characteristics of the gear pump under typical operating conditions are calculated and discussed. The technique presented in this paper can be regarded as a useful tool for optimization design of gear pumps in vehicle engineering.

Optimal design of gear pumps for exhaust gas aftertreatment applications

In this paper an innovative procedure for determining the optimal design of an external spur gear pump for a particular emission reduction application in automobiles has been proposed. The pump forms the main part of a mechatronic system that controls the flow rate of a mixture of urea in water to catalytically reduce emissions in diesel engines. The proposed research proves to be an advance in gear machine design by using a multi-objective based genetic algorithm, to determine the optimal design of the gears and the casing by maximizing the volumetric efficiency, minimizing pressure overshoots, localized cavitation and noise emissions. The research uses HYGESim (HYdraulic GEar machines Simulator) simulation tool, which is being developed by the authors’ research group, for calculating the important performance features of the machine. The best designs for the machine based on enhancement in performance are presented. Results in terms of simulations and tests which validate the effectiveness of the proposed novel design methodology are also presented.

External Gear Pump Model and Simulation

This paper describes the development of gear pumps and the main causes of noise,and establish the overall dynamic model of external gear pump,mainly including the trapped oil model,the gear mesh model and the shell model and then go on with simulation analysis and research.Through establishment the gear pump model,it is benefit for predicting the gear pump trapped oil pressure and studying the impact of parameter changes on the pressure,and getting the natural frequencies and model shapes of the gear pump structural system,so that we can analysis external gear pump vibration and assess gear pump design optimization,while helping to find the effective measures to control gear pump noise and ease trapped oil phenomenon.

Applying envelope theory and deviation function to tooth profile design

In this work, a mathematical model of an elastic conjugate element is presented, using envelope theory and a deviation function. A basic deformation curve in a two-dimensional system is defined, and determined by the maximum deformation of the originally generated curve. The set of these points of maximum deformation in the moving coordinate frame determines the deviation of the originally generated curve. The degree of deviation is described by a deviation function. A deviation function is chosen to reshape the originally generated curve. The reshaped curve is called a basic deformation curve. If the basic deformation curve is known, an envelope associated with them can be determined. The results are applied to rotary gear pump design. The reshaped curve is superior to the originally generated curve. The reshaped curve has lower deformation, von-Mises stress, and greater bending strength than the originally generated curve. This investigation indicates that envelope theory and deviation function can avoid singular points of conjugate elements, using an example.