Housing Influence on Churning Losses in Geared Transmissions

2007 ◽  
Author(s):  
C. Changenet ◽  
P. Velex
Keyword(s):  
Fluid Flow ◽  
Qualitative Evaluation ◽  
Flow Regimes ◽  
Power Losses ◽  
Test Rig ◽  
Automotive Transmission ◽  
Transmission Geometry ◽  
Analytical Formulas ◽  
Set Up ◽  
Fluid Flow Regimes

In a previous paper, a series of analytical formulas were presented enabling accurate predictions of churning losses for one gear which is typical of automotive transmission geometry. However, this formulation does not take into account the influence of flanges and deflectors. In order to extend the proposed methodology, a test rig has been set up in which several moveable walls can be inserted thus making it possible to modify the radial and axial clearances, i.e., the distances between the tested gear and the walls. Based on a qualitative evaluation of the various fluid flow regimes possible in gearboxes, the influence of the global volume of the oil sump on churning losses is analyzed. By considering a number of flange and deflector arrangements, the following conclusions are drawn: a) radial clearances have a weaker influence than axial clearances and, b) power losses can be minimized by properly chosen axial clearances.

Housing Influence on Churning Losses in Geared Transmissions

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
C. Changenet ◽  
P. Velex
Keyword(s):  
Fluid Flow ◽  
Qualitative Evaluation ◽  
Power Losses ◽  
Test Rig ◽  
Empirical Formulas ◽  
Preliminary Results ◽  
Automotive Transmission ◽  
Transmission Geometry ◽  
Set Up ◽  
Fluid Flow Regimes

In a previous paper (Changenet, and Velex, 2007, “A Model for the Prediction of Churning Losses in Geared Transmissions—Preliminary Results,” ASME J. Mech. Des., 129(1), pp. 128–133), a series of empirical formulas were presented enabling accurate predictions of churning losses for one gear, which is typical of automotive transmission geometry. However, this formulation does not take into account the influence of flanges and deflectors. In order to extend the proposed methodology, a test rig has been set up in which several movable walls can be inserted, thus making it possible to modify the radial and axial clearances, i.e., the distances between the tested gear and the walls. Based on a qualitative evaluation of the various fluid flow regimes possible in gearboxes, the influence of the global volume of the oil sump on churning losses is analyzed. By considering a number of flange and deflector arrangements, the following conclusions are drawn: (a) Radial clearances have a weaker influence than axial clearances and (b) power losses can be minimized by properly chosen axial clearances.

scholarly journals Topological inversions in coalescing granular media control fluid-flow regimes

2017 ◽  
Vol 96 (3) ◽  
Author(s):  
Fabian B. Wadsworth ◽  
Jérémie Vasseur ◽  
Edward W. Llewellin ◽  
Katherine J. Dobson ◽  
Mathieu Colombier ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Granular Media ◽  
Flow Regimes ◽  
Media Control ◽  
Control Fluid ◽  
Fluid Flow Regimes

scholarly journals INTEGRATED MODEL «RESERVOIR - WELL - PUMP» FOR UNSTEADY FLUID FLOW REGIMES CALCULATING

2021 ◽  
Vol 19 (1) ◽  
pp. 33
Author(s):  
A.A. Pashali ◽  
R.S. Khalfin ◽  
D.V. Silnov ◽  
A.S. Topolnikov ◽  
B.M. Latypov ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Flow Regimes ◽  
Integrated Model ◽  
Unsteady Fluid Flow ◽  
Unsteady Fluid ◽  
Fluid Flow Regimes

A Note on Flow Regimes and Churning Loss Modelling

2011 ◽  
Author(s):  
C. Changenet ◽  
G. Leprince ◽  
F. Ville ◽  
P. Velex
Keyword(s):  
Critical Reynolds Number ◽  
Flow Regimes ◽  
Operating Conditions ◽  
Power Losses ◽  
Secondary Importance ◽  
Helical Gears ◽  
Viscous Forces ◽  
Physical Mechanisms ◽  
Loss Modelling ◽  
Fluid Flow Regimes

The purpose of this study is to investigate the various fluid flow regimes generated by a pinion running partly immersed in an oil bath and the corresponding churning power losses. In a series of papers, the authors have established several loss formulae whose validity depends on two different flow regimes characterized via a critical Reynolds number. Based on some new measurements for transient operating conditions, it has been found that the separation in two regimes may be not accurate enough for wide-faced gears and high temperatures. An extended formulation is therefore proposed which, apart from viscous forces, introduces the influence of centrifugal effects. The corresponding results agree well with the experimental measurements from a number of gears and operating conditions (speed, temperature). Finally, the link between churning and windage losses is examined and it is concluded that the physical mechanisms are different thus making it difficult to establish a general correlation between the two phenomena. In particular, it is shown that tooth geometry is of secondary importance on churning whereas, the air-lubricant circulation being different for spur and helical gears, it substantially impacts windage.

scholarly journals Multi-Pulse Diode Rectifier for More-Electric Aircraft Applications: Parallel versus Series Topologies

2017 ◽  
Vol 13 (1) ◽  
pp. 138-144
Author(s):  
Ahmed Hafez ◽  
Ali Yousef
Keyword(s):  
Test Rig ◽  
Grid Systems ◽  
Aircraft Systems ◽  
Electric Aircraft ◽  
Analytical Formulas ◽  
Key Variables ◽  
Set Up ◽  
The Impact ◽  
More Electric Aircraft

This article analyzes thoroughly the performance of the Multi-Pulse Diode Rectifiers (MPDRs) regarding the quality of input/output voltage and currents. Two possible arrangements of MPDRs are investigated: series and parallel. The impact of the DC side connection on the performance of the MPDRs regarding the operation parameters and rectifier indices are comprehensively examined. Detailed analytical formulas are advised to identify clearly the key variables that control the operation of MPDRs. Moreover, comprehensive simulation results are presented to quantify the performance and validate the analytical analysis. Test-rig is set up to recognize the promising arrangement of MPDRs. Significant correlation is there between simulation and practical results. The analytical results are presented for aircraft systems (400Hz), and power grid systems (60Hz). This is to study the impact of voltage and frequency levels on the topology type of MPDRs. In general, each topology shows merits and have limitations.

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