Experimental identification and modelling of flow and torque losses in gerotor hydraulic motors

Conrad, Finn; Trostmann, Erik; Zhang, Muzhi

doi:10.5739/isfp.1993.677

Cited by 6 publications

(5 citation statements)

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“…In 1970, the original author, having conducted hundreds of tests on both pumps and motors, of both fixed and variable displacement types, prepared a technical paper [1] on an empirical method for determining the displacement of positive displacement pumps and motors. This paper has been cited by a number of other authors, notably, Post [2], Conrad et al [3], and Ivantysyn and Ivantysynova [4]. Anecdotally, the method has been adopted by an unknown number of individuals working in hydraulic laboratories around the world.…”

Section: Introductionmentioning

confidence: 99%

“…Likewise, Post [2] also compared three methods for the determination of the displacement of a hydraulic machine; after his study, he concluded that this method was preferable to the existing ISO method. Conrad et al [3] preferred the use of this method for the validation of their mathematical model of the flow and torque loss of a pump. According to Myszkowski [8] and Czyński [9], the work of Balawender from 1988 detailed a careful analysis of the energy losses in hydraulic equipment using an energy balance approach.…”

Section: Introductionmentioning

confidence: 99%

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The Determination of the Theoretical Stroke Volume of Hydrostatic Positive Displacement Pumps and Motors from Volumetric Measurements

Toet

Johnson²,

Montague

et al. 2019

Energies

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This document presents a revised translation to the English language work developed more than 40 years ago by the first author. It further summarizes a common misinterpretation of the method and succinctly describes a graphical procedure to correctly determine the derived displacement volume of a pump or a motor. The original work contains a directive for the determination of the derived displacement volume of hydrostatic positive displacement pumps and motors, from volumetric (flow and speed) measurements. The procedure is based on the definition of the derived displaced volume, defined as: The volumetric flow pushed or admitted by hydrostatic positive displacement pumps and motors per (shaft) revolution, at zero internal and external leakage flow conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Determination of the Theoretical Stroke Volume of Hydrostatic Positive Displacement Pumps and Motors from Volumetric Measurements

Toet

Johnson²,

Montague

et al. 2019

Energies

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“…The total efficiency is very much related to losses. Experimental and torque losses in gerotor were investigated in case of hydrostatic machines which represent complex fluid dynamic systems due to intricate and partially unknown dynamics [8]. Some losses are related to tribological behaviour.…”

Section: Literature Reviewmentioning

confidence: 99%

The Pressure and Efficiency Characteristic of Hydraulic Gerotor Motor with the Floating Outer Ring

Strmčnik

Majdič

2018

Teh. vjesn.

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A gerotor with the floating outer ring is a low speed high torque hydraulic motor. It is a special type of hydraulic motor, which is very rarely described in literature. In this study, the pressure and efficiency characteristics of hydraulic gerotor motor were investigated. The main purpose of this scientific paper was to analyse the influence of the size of the holes in the valve plate on total efficiency of the gerotor. The total efficiency is the most important and prominent information about energy conversion of hydraulic components such as hydraulic motors and pumps. The operation of gerotor is briefly described as well as some equations for the determination of efficiency. In a section of the methodology, a measurement procedure is presented in detail. A test rig with hydraulic components and sensors was introduced. The analysis was carried out to respect the international standards. With the help of measurement, we determined the pressure distribution in some specific chambers in the hydraulic gerotor motor. The results show that there is correlation between the size of holes in the valve plate and the total efficiency of the gerotor. Furthermore, a very high total efficiency was obtained with the hole size of Φ6,3 mm. In that case, the total efficiency was on average 5% higher in comparison to the initial hole size of Φ5,5 mm.

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“…More sophisticated methods like the one presented by Eggers, et al [6] were used to describe a mathematical interpolation procedure called POLYMOD, which was used for developing a torque and flow model based on a polynomial fit of experimental test data. Similarly, Conrad et al [7] developed a loss model where the flow losses could be obtained from fitting experimental data to a line. Whether the aim is to obtain a complete flow model or simply for determining the volumetric displacement of the pump or motor, a set of experimental data points is required.…”

Section: Introductionmentioning

confidence: 99%

Strategies to Minimize Data Sample Size for Regression-Based Pump/Motor Models

Johnson¹,

Garcia-Bravo²,

Panwar³

et al. 2021

Linköping Electronic Conference Proceedings

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This work presents an analysis for tracking the evolution of regression coefficients and the Root-Mean-Square of their residuals on a test dataset for a hydraulic pump. The method starts by iteratively regressing data points that are undergoing sequencing by adding one new data sample at a time, then regressing with each iteration. This process was named Progressively Sequenced Regression Analysis, shortened to “PSR analysis” in this paper. The motivating and guiding postulate of PSR analysis is based on the belief that a plateau of the regression coefficients and statistical figures of merit had to exist if sampling theory is accepted to be real. It was anticipated at the outset that both the regression coefficients and the Residual RMS would converge on respective plateau values; however, it was discovered that the coefficients were very volatile, with some, more volatile than others. Tracking the Residual RMS was found to produce the more reliable measure of information saturation because the convergence is more obvious, provided that the sample sequencing was done with the experience learned from performing PSR analysis. This document is focused on explaining how orthogonally sequenced data can be mined for the limits or hyperspace vertexes of the sampled data, and the source data optimally sequenced (rearranged) to produce results that are as efficacious as Latin Hypercube (LHC) sampling for achieving information saturation at a predictable number of samples. PSR analysis has led to an objective method for verifying that the proper arrangement, i.e., optimized sequencing, of the source data set can predict the condition of information saturation and minimum useful sample size. It ends with a postulate of how this can be achieved using a combination of LHC sampling and vertex pre-test planning, or vertex mining of legacy data. The content of this paper has concentrated solely on the output flow model of hydraulic, positive displacement pumps.

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Experimental identification and modelling of flow and torque losses in gerotor hydraulic motors

Cited by 6 publications

References 0 publications

The Determination of the Theoretical Stroke Volume of Hydrostatic Positive Displacement Pumps and Motors from Volumetric Measurements

The Determination of the Theoretical Stroke Volume of Hydrostatic Positive Displacement Pumps and Motors from Volumetric Measurements

The Pressure and Efficiency Characteristic of Hydraulic Gerotor Motor with the Floating Outer Ring

Strategies to Minimize Data Sample Size for Regression-Based Pump/Motor Models

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