scholarly journals Mechanical Hybrid KERS Based on Toroidal Traction Drives: An Example of Smart Tribological Design to Improve Terrestrial Vehicle Performance

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Francesco Bottiglione ◽  
Giuseppe Carbone ◽  
Leonardo De Novellis ◽  
Luigi Mangialardi ◽  
Giacomo Mantriota
Keyword(s):  
Energy Recovery ◽  
Elastohydrodynamic Lubrication ◽  
Mechanical Efficiency ◽  
Speed Ratio ◽  
Vehicle Performance ◽  
Lubrication Regimes ◽  
Recovery Potential ◽  
Wide Range ◽  
Unit Speed ◽  
Traction Drives

We analyse in terms of efficiency and traction capabilities a recently patented traction drive, referred to as the double roller full-toroidal variator (DFTV). We compare its performance with the single roller full-toroidal variator (SFTV) and the single roller half-toroidal variator (SHTV). Modeling of these variators involves challenging tribological issues; the traction and efficiency performances depend on tribological phenomena occurring at the interface between rollers and disks, where the lubricant undergoes very severe elastohydrodynamic lubrication regimes. Interestingly, the DFTV shows an improvement of the mechanical efficiency over a wide range of transmission ratios and in particular at the unit speed ratio as in such conditions in which the DFTV allows for zero-spin, thus strongly enhancing its traction capabilities. The very high mechanical efficiency and traction performances of the DFTV are exploited to investigate the performance of a flywheel-based Kinetic Energy Recovery System (KERS), where the efficiency of the variator plays an important role in determining the overall energy recovery performance. The energy boost capabilities and the round-trip efficiency are calculated for the three different variators considered in this study. The results suggest that the energy recovery potential of the mechanical KERS can be improved with a proper choice of the variator.

Traction and Efficiency Performance of the Double Roller Full-Toroidal Variator: A Comparison With Half- and Full-Toroidal Drives

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
L. De Novellis ◽  
G. Carbone ◽  
L. Mangialardi
Keyword(s):  
Mechanical Efficiency ◽  
The Other ◽  
Classical Solutions ◽  
Speed Ratio ◽  
Traction Drive ◽  
Torque Transmission ◽  
Wide Range ◽  
Efficiency Performance ◽  
Unit Speed ◽  
Toroidal Traction

In this paper, we analyze in terms of efficiency and traction capabilities a recently patented toroidal traction drive variator: the so-called double roller full-toroidal variator (DFTV). By employing a relatively simple model of the elastohydrodynamic contact behavior between the disks and rollers, we compare the performance of the DFTV with classical solutions as the single-roller full-toroidal variator (SFTV) and the single-roller half-toroidal variator (SHTV). Interestingly, the DFTV shows an improvement of the mechanical efficiency over a wide range of transmission ratios, and in particular at the unit speed ratio, as in such conditions the DFTV allows for zero-spin thus strongly enhancing its traction capabilities. The relation between the torque transmission and the operational volume is also investigated for the three toroid geometries. In this case, the better performance is achieved by the SHTV, whereas the other two geometries show a similar behavior.

A Model of Mixed Lubrication Based on Non-Normalized Discretization and Its Application for Multilayered Materials

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Qingbing Dong ◽  
Zhanjiang Wang ◽  
Dong Zhu ◽  
Fanming Meng ◽  
Lixin Xu ◽  
...  
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Functional Materials ◽  
Computational Procedure ◽  
Pressure Balance ◽  
Engineering Structures ◽  
Lubrication Regimes ◽  
Lubrication Performance ◽  
Wide Range ◽  
Full Analysis ◽  
Multilayered Materials

This study presents a generalized model of mixed elastohydrodynamic lubrication, in which the dimensional Reynolds equation is discretized according to a modified differential scheme based on the full analysis of the pressure balance within the lubrication region. The model is capable of a wide range of lubrication regimes from fully hydrodynamic down to boundary lubrication, and both the steady-state and the time-dependent conditions can be considered. A simplified computational procedure is proposed for elliptical contacts without the ellipticity parameters specified. The evolution of lubrication behavior at startup and shutdown conditions is investigated and the transient effect of surface waviness is discussed. The model application is then extended to contacts of multilayered materials, and the effects of the layer stiffness and the fabrication methods on the stress fields and lubrication performance are analyzed. The conclusions may potentially provide some insightful information for the design and analysis of functional materials and their engineering structures.

Experimental and Numerical Investigations of the Stribeck Curves for Lubricated Counterformal Contacts

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Tao He ◽  
Dong Zhu ◽  
Jiaxu Wang ◽  
Q. Jane Wang
Keyword(s):  
Shear Stress ◽  
Elastohydrodynamic Lubrication ◽  
Stribeck Curve ◽  
Boundary Lubrication Friction ◽  
Lubrication Regimes ◽  
Limiting Shear Stress ◽  
Wide Range ◽  
Basic Characteristics ◽  
Stribeck Curves ◽  
Film Lubrication

The Stribeck curve is an important means to demonstrate the frictional behavior of a lubricated interface during the entire transition from boundary and mixed to full-film lubrication. In the present study, a new test apparatus has been built that can operate under rolling–sliding conditions at a continuously variable speed in an extremely wide range, approximately from 0.00006 to 60 m/s, covering six orders of magnitude. Hence, a complete Stribeck curve can be measured to reveal its basic characteristics for lubricated counterformal contacts. The measured curves are compared with numerical simulation results obtained from an available unified mixed elastohydrodynamic lubrication (EHL) model that is also capable of handling cases during the entire transition. A modified empirical model for the limiting shear stress of lubricant is obtained, and a good agreement between the measured and calculated Stribeck curves is achieved for the tested base oils in all the three lubrication regimes, which thus well validates the simulation methods employed. Both the experimental and numerical results indicate that the Stribeck curves for counterformal contact interfaces behave differently from those for conformal contacts. When the rolling speed increases at a fixed slide-to-roll ratio, the friction continuously decreases even in the full-film lubrication regime due to the reduction of the lubricant limiting shear stress caused mainly by the rise of the surface flash temperature. In addition, the test results indicate that the boundary additives in a commodity lubricant may have considerable influence on the boundary lubrication friction but that on the friction in the mixed and full-film lubrication appears to be limited.

Energy recovery potential in coupling of sanitation and agriculture: Techno-economic analysis on resource-oriented sanitation

2021 ◽  
Vol 126 ◽  
pp. 141-151
Author(s):  
Mingjie Xu ◽  
Yu Zhang ◽  
Yahui Li ◽  
Minghuan Lv ◽  
Shikun Zhu ◽  
...  
Keyword(s):  
Economic Analysis ◽  
Energy Recovery ◽  
Recovery Potential

scholarly journals Energy Recovery Potential in Industrial and Municipal Wastewater Networks Using Micro-Hydropower in Spain

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 691
Author(s):  
Aida Mérida García ◽  
Juan Antonio Rodríguez Díaz ◽  
Jorge García Morillo ◽  
Aonghus McNabola
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Energy Recovery ◽  
Energy Production ◽  
Municipal Wastewater ◽  
Distribution Networks ◽  
Total Power ◽  
Energy Potential ◽  
Total Energy Consumption ◽  
Recovery Potential

The use of micro-hydropower (MHP) for energy recovery in water distribution networks is becoming increasingly widespread. The incorporation of this technology, which offers low-cost solutions, allows for the reduction of greenhouse gas emissions linked to energy consumption. In this work, the MHP energy recovery potential in Spain from all available wastewater discharges, both municipal and private industrial, was assessed, based on discharge licenses. From a total of 16,778 licenses, less than 1% of the sites presented an MHP potential higher than 2 kW, with a total power potential between 3.31 and 3.54 MW. This total was distributed between industry, fish farms and municipal wastewater treatment plants following the proportion 51–54%, 14–13% and 35–33%, respectively. The total energy production estimated reached 29 GWh∙year−1, from which 80% corresponded to sites with power potential over 15 kW. Energy-related industries, not included in previous investigations, amounted to 45% of the total energy potential for Spain, a finding which could greatly influence MHP potential estimates across the world. The estimated energy production represented a potential CO2 emission savings of around 11 thousand tonnes, with a corresponding reduction between M€ 2.11 and M€ 4.24 in the total energy consumption in the country.

A Starved Mixed Elastohydrodynamic Lubrication Model for the Prediction of Lubrication Performance, Friction and Flash Temperature With Arbitrary Entrainment Angle

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Wei Pu ◽  
Dong Zhu ◽  
Jiaxu Wang
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Flash Temperature ◽  
Machined Surface ◽  
Lubrication Performance ◽  
Wide Range ◽  
Starved Lubrication

In this study, a modified mixed lubrication model is developed with consideration of machined surface roughness, arbitrary entraining velocity angle, starvation, and cavitation. Model validation is executed by means of comparison between the obtained numerical results and the available starved elastohydrodynamic lubrication (EHL) data found from some previous studies. A comprehensive analysis for the effect of inlet oil supply condition on starvation and cavitation, mixed EHL characteristics, friction and flash temperature in elliptical contacts is conducted in a wide range of operating conditions. In addition, the influence of roughness orientation on film thickness and friction is discussed under different starved lubrication conditions. Obtained results reveal that inlet starvation leads to an obvious reduction of average film thickness and an increase in interasperity cavitation area due to surface roughness, which results in significant increment of asperity contacts, friction, and flash temperature. Besides, the effect of entrainment angle on film thickness will be weakened if the two surfaces operate under starved lubrication condition. Furthermore, the results show that the transverse roughness may yield thicker EHL films and lower friction than the isotropic and longitudinal if starvation is taken into account. Therefore, the starved mixed EHL model can be considered as a useful engineering tool for industrial applications.

Performance Estimation of Axial Flow Turbines

1970 ◽  
Vol 185 (1) ◽  
pp. 407-424 ◽  
Author(s):  
H. R. M. Craig ◽  
H. J. A. Cox
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Axial Flow ◽  
Performance Estimation ◽  
Speed Ratio ◽  
Test Results ◽  
Wide Range ◽  
Relevant Variables

A comprehensive method of estimating the performance of axial flow steam and gas turbines is presented, based on analysis of linear cascade tests on blading, on a number of turbine test results, and on air tests of model casings. The validity of the use of such data is briefly considered. Data are presented to allow performance estimation of actual machines over a wide range of Reynolds number, Mach number, aspect ratio and other relevant variables. The use of the method in connection with three-dimensional methods of flow estimation is considered, and data presented showing encouraging agreement between estimates and available test results. Finally ‘carpets’ are presented showing the trends in efficiencies that are attainable in turbines designed over a wide range of loading, axial velocity/blade speed ratio, Reynolds number and aspect ratio.

Elastohydrodynamic Lubrication of Soft-Layered Solids at Elliptical Contacts: Part 1: Elasticity Analysis

1994 ◽  
Vol 208 (1) ◽  
pp. 31-41 ◽  
Author(s):  
J Q Yao ◽  
D Dowson
Keyword(s):  
Aspect Ratio ◽  
Surface Deformation ◽  
Applied Pressure ◽  
Numerical Procedure ◽  
Elastohydrodynamic Lubrication ◽  
Thin Layers ◽  
Elasticity Analysis ◽  
Synovial Joint ◽  
Wide Range ◽  
Non Linear System

In this two-part paper we consider the elastohydrodynamic lubrication (EHL) of soft-layered solids representing elliptical contacts. The problem has not previously attracted much attention, partly due to the lack of an effective numerical procedure to solve the coupled non-linear system of equations, but it is essential to the proper design of bearings with soft elastomeric liners and the full understanding of synovial joint lubrication. In Part 1, the elasticity analysis for the surface deformation of a low elastic modulus layer on a hard-backing half-space under various forms of normal loadings is considered, by means of both the rigorous Hankel transform method and various simplifications. For layers of compressible materials (v ≤ 0.4), a generalized foundation model described by a second-order differential equation is proposed to represent the relationship between the surface deformation and the applied pressure. The empirical equation developed in this study is valid for a very wide range of the aspect ratio of the contact and provides an alternative way of modelling the elastic deformation without recourse to the often tedious integration in the numerical analysis of the EHL problem. The simplest form (constrained column model) of the equation, where the surface deformation is directly proportional to the local applied pressure, was found to be reasonably accurate for compressible thin layers (the aspect ratio 2b/ht ≥ 5 and Poisson's ratio v ≤ 0.4).

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