On the Influence of Lubricant Supply Conditions and Bearing Configuration to the Performance of (Semi) Floating Ring Bearing Systems for Turbochargers

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Luis San Andrés ◽  
Feng Yu ◽  
Kostandin Gjika
Keyword(s):  
Thermal Energy ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Engine Oil ◽  
Large Temperature ◽  
Oil Viscosity ◽  
Supply Pressure ◽  
Oil Flow ◽  
The Impact ◽  
Bearing System

Engine oil-lubricated (semi) floating ring bearing ((S)FRB) systems in passenger vehicle turbochargers (TC) operate at temperatures well above ambient and must withstand large temperature gradients that can lead to severe thermomechanical induced stresses. Physical modeling of the thermal energy flow paths and an effective thermal management strategy are paramount to determine safe operating conditions ensuring the TC component mechanical integrity and the robustness of its bearing system. The paper details a model to predict the pressure and temperature fields and the distribution of thermal energy flows in a bearing system. The impact of lubricant supply conditions, bearing film clearances, and oil supply grooves is quantified. Either a low oil temperature or a high supply pressure increases the generated shear power. Either a high supply pressure or a large clearance allows more flow through the inner film and draws more heat from the hot journal, thought it increases the shear drag power as the oil viscosity remains high. Nonetheless, the peak temperature of the inner film is not influenced by the changes on the way the oil is supplied into the film as the thermal energy displaced from the hot shaft into the film is overwhelming. Adding axial grooves on the inner side of the (S)FRB improves its dynamic stability, albeit increasing the drawn oil flow as well as the drag power and heat from the shaft. The results identify a compromise between different parameters of groove designs thus enabling a bearing system with a low power consumption.

The Influence of Lubricant Supply Conditions and Bearing Configuration on the Performance of (Semi) Floating Ring Bearing Systems for Turbochargers

2017 ◽  
Author(s):  
Luis San Andrés ◽  
Feng Yu ◽  
Kostandin Gjika
Keyword(s):  
Heat Flow ◽  
Thermal Energy ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Engine Oil ◽  
Large Temperature ◽  
Oil Viscosity ◽  
Supply Pressure ◽  
The Impact ◽  
Bearing System

Engine oil lubricated (semi) floating ring bearing (S)FRB systems in passenger vehicle turbochargers (TC) operate at temperatures well above ambient and must withstand large temperature gradients that can lead to severe thermo-mechanical induced stresses. Physical modeling of the thermal energy flow paths and an effective thermal management strategy are paramount to determine safe operating conditions ensuring the TC component mechanical integrity and the robustness of its bearing system. On occasion, the selection of one particular bearing parameter to improve a certain performance characteristic could be detrimental to other performance characteristics of a TC system. The paper details a thermohydrodynamic model to predict the hydrodynamic pressure and temperature fields and the distribution of thermal energy flows in the bearing system. The impact of the lubricant supply conditions (pressure and temperature), bearing film clearances, oil supply grooves on the ring ID surface are quantified. Lubricating a (S)FRB with either a low oil temperature or a high supply pressure increases (shear induced) heat flow. A lube high supply pressure or a large clearance allow for more flow through the inner film working towards drawing more heat flow from the hot journal, yet raises the shear drag power as the oil viscosity remains high. Nonetheless, the peak temperature of the inner film is not influenced much by the changes on the way the oil is supplied into the film as the thermal energy displaced from the hot shaft into the film is overwhelming. Adding axial grooves on the inner side of the (S)FRB improves its dynamic stability, albeit increasing the drawn oil flow as well as the drag power and heat flow from the shaft. The predictive model allows to identify a compromise between different parameters of groove designs thus enabling a bearing system with a low power consumption.

On the Effect of Thermal Energy Transport to the Performance of (Semi)Floating Ring Bearing Systems for Automotive Turbochargers

2012 ◽  
Author(s):  
Luis San Andrés ◽  
Vince Barbarie ◽  
Avijit Bhattacharya ◽  
Kostandin Gjika
Keyword(s):  
Heat Flow ◽  
Thermal Energy ◽  
Energy Transport ◽  
Operating Conditions ◽  
Engine Oil ◽  
Distinct Advantage ◽  
Oil Viscosity ◽  
Wide Range ◽  
Thermal Energy Transport ◽  
Bearing System

Bearing systems in engine-oil lubricated turbochargers (TCs) must operate reliably over a wide range of shaft speeds and withstanding severe axial and radial thermal gradients. An engineered thermal management of the energy flows into and out of the bearing system is paramount to ensure the components mechanical integrity and the robustness of the bearing system. The bearings, radial and thrust type, act both as a load bearing and low friction support with the lubricant carrying away a large fraction of the thermal energy generated by rotational drag and the heat flow disposed from a hot shaft. The paper introduces a thermohydrodynamic analysis for prediction of the pressure and temperature fields in a (semi) floating ring bearing system. The analysis solves simultaneously the Reynolds equation with variable oil viscosity and the thermal energy transport equation in the inner and outer films of the bearing system. Flow conditions in both films are coupled to the temperature distribution and heat flow thru the (semi)floating ring. Other constraints include calculating the fluid films’ forces reacting to the externally applied load and to determine the operating journal and ring eccentricities. Predictions of performance for a unique realistic (S)FRB configuration at typical TC operating conditions reveal distinct knowledge: (a) the heat flow from the shaft into the inner film is overwhelming, in particular at the inlet lubricant plane where the temperature difference with the cold oil is largest; (b) the inner film temperature increases quickly as soon as the (cold) lubricant enters the film and due to the large amount of energy generated by shear drag and the heat transfer from the shaft; (c) a floating ring develops a significant radial temperature gradient; (d) at all shaft speeds, low and high, the thermal energy carried away by the lubricant streams is no less that 70% of the total energy input; the rest is conducted through the TC casing. To warrant this thermal energy distribution, enough lubricant flow must be supplied to the bearing system. The efficient computational model offers a distinct advantage over existing lumped parameters thermal models and with no penalty in execution time.

On the Effect of Thermal Energy Transport to the Performance of (Semi) Floating Ring Bearing Systems for Automotive Turbochargers

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Luis San Andrés ◽  
Vince Barbarie ◽  
Avijit Bhattacharya ◽  
Kostandin Gjika
Keyword(s):  
Heat Flow ◽  
Thermal Energy ◽  
Energy Transport ◽  
Operating Conditions ◽  
Engine Oil ◽  
Distinct Advantage ◽  
Oil Viscosity ◽  
Wide Range ◽  
Thermal Energy Transport ◽  
Bearing System

Bearing systems in engine-oil lubricated turbochargers (TCs) must operate reliably over a wide range of shaft speeds and withstand severe axial and radial thermal gradients. An engineered thermal management of the energy flows into and out of the bearing system is paramount in order to ensure the component’s mechanical integrity and the robustness of the bearing system. The bearings, radial and thrust type, act both as a load bearing and low friction support with the lubricant carrying away a large fraction of the thermal energy generated by rotational drag and the heat flow disposed from a hot shaft. The paper introduces a thermohydrodynamic analysis for the prediction of the pressure and temperature fields in a (semi) floating ring bearing (S)FRB system. The analysis simultaneously solves the Reynolds equation with variable oil viscosity and the thermal energy transport equation in the inner and outer films of the bearing system. Flow conditions in both films are coupled to the temperature distribution and heat flow through the (semi) floating ring. Other constraints include calculating the fluid films’ forces reacting to the externally applied load and to determine the operating journal and ring eccentricities. The predictions of performance for a unique realistic (S)FRB configuration at typical TC operating conditions reveal a distinct knowledge: (a) the heat flow from the shaft into the inner film is overwhelming, in particular, at the inlet lubricant plane where the temperature difference with the cold oil is largest; (b) the inner film temperature quickly increases as soon as the (cold) lubricant enters the film and is due to the large amount of energy generated by shear drag and the heat transfer from the shaft; (c) a floating ring develops a significant radial temperature gradient; (d) at all shaft speeds, low and high, the thermal energy carried away by the lubricant streams is no less than 70% of the total energy input; the rest is conducted through the TC casing. To warrant this thermal energy distribution, enough lubricant flow must be supplied to the bearing system. The efficient computational model offers a distinct advantage over existing lumped parameters thermal models and there is no penalty in the execution time.

An Experimental Analysis of Misalignment Effects on Hydrodynamic Plain Journal Bearing Performances

2001 ◽  
Vol 124 (2) ◽  
pp. 313-319 ◽  
Author(s):  
J. Bouyer ◽  
M. Fillon
Keyword(s):  
Film Thickness ◽  
Journal Bearing ◽  
Hydrodynamic Pressure ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Maximum Pressure ◽  
Minimum Film Thickness ◽  
Oil Flow ◽  
Hydrodynamic Effects

The present study deals with the experimental determination of the performance of a 100 mm diameter plain journal bearing submitted to a misalignment torque. Hydrodynamic pressure and temperature fields in the mid-plane of the bearing, temperatures in two axial directions, oil flow rate, and minimum film thickness, were all measured for various operating conditions and misalignment torques. Tests were carried out for rotational speeds ranging from 1500 to 4000 rpm with a maximum static load of 9000 N and a misalignment torque varying from 0 to 70 N.m. The bearing performances were greatly affected by the misalignment. The maximum pressure in the mid-plane decreased by 20 percent for the largest misalignment torque while the minimum film thickness was reduced by 80 percent. The misalignment caused more significant changes in bearing performance when the rotational speed or load was low. The hydrodynamic effects were then relatively small and the bearing offered less resistance to the misalignment.

Experimental and numerical investigation on thermodynamic performance of full-floating ring bearings with circumferential oil groove

2019 ◽  
Vol 233 (8) ◽  
pp. 1182-1196
Author(s):  
Congcong Zhang ◽  
Rixiu Men ◽  
Yongliang Wang ◽  
Hong He ◽  
Wei Chen
Keyword(s):  
Thermal Energy ◽  
Separation Of Variables ◽  
Large Fraction ◽  
Engine Oil ◽  
Speed Ratio ◽  
Operating Parameters ◽  
Thermal Gradients ◽  
Oil Supply ◽  
Thermodynamic Performance ◽  
Oil Flow

Floating ring bearing systems in engine-oil lubricated turbochargers commonly withstand severe radial and axial thermal gradients. An engineered thermal management of the heat flows out of the bearing system is paramount in order to ensure the component's mechanical integrity and the reliability of the bearing systems. Therefore, oil flow plays an important role in maintaining an uninterrupted oil film and removing a large fraction of the thermal energy generated by rotational drag and the heat flow disposed from a hot shaft to cool the bearings. The floating rings usually feature circumferential oil groove on their outer surfaces for the increase of flow rate. This work presents experimental and numerical investigations into the operating parameters of full-floating ring bearings with a circumferential oil groove. A comprehensive model, including a transient form of thermal energy balance, is built to analyze relevant bearing parameters like temperature distribution, mechanical power loss, and ring speed ratio for various oil supply conditions. The Reynolds equation is solved by a separation of variables method satisfying the appropriate boundary conditions. For model validation purposes, an extensive experimental study on a cold-gas turbocharger test bench was conducted. As with the test data, the predictions show that oil supply conditions lead to different degrees of influence on the operating parameters of the investigated floating ring bearings.

Off-Design of a Pumped Thermal Energy Storage Based on Closed Brayton Cycles

2021 ◽  
Author(s):  
Guido Francesco Frate ◽  
Luigia Paternostro ◽  
Lorenzo Ferrari ◽  
Umberto Desideri
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Electric Energy ◽  
Packed Bed ◽  
Operating Conditions ◽  
Part Load ◽  
Storage Technologies ◽  
Thermodynamical Behavior ◽  
The Impact

Abstract The growth of renewable energy source requires reliable, durable and cheap storage technologies. In this field, the Pumped Thermal Energy Storage (PTES), is drawing some interest as it appears not to be affected by geographical limitations and use very cheap materials. PTES is less efficient than pumped hydro and batteries, but it could achieve satisfactory efficiencies, show better economic performance and be characterized by negligible environmental impacts. A PTES stores the electric energy as thermal exergy in solid packed beds, by operating two closed Brayton cycles, one for charging and the other one for discharging. Although PTES thermodynamical behavior is well understood, the interaction between the components is rarely investigated. This study investigates the impact of packed-bed behavior on turbomachines operating conditions. In this way, PTES off-design and part-load performance are estimated. A control strategy especially suited for closed Brayton cycles, i.e. the inventory control, is used to control the system. As it resulted, PTES is characterized by an excellent part-load performance, which might be a significant advantage over the competing technologies. However, the off-design operation induced by the packed-bed thermal behavior might significantly reduce the system performance and, in particular, that of the discharge phase.

The Impact of Model Assumptions on the CFD Assisted Design of Gas Turbine Packages

2019 ◽  
Author(s):  
Gabriele Lucherini ◽  
Vittorio Michelassi ◽  
Stefano Minotti
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Structural Integrity ◽  
Ventilation System ◽  
Gas Diffusion ◽  
Computational Effort ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Fuel Gas ◽  
The Impact

Abstract A gas turbine is usually installed inside a package to reduce the acoustics emissions and protect against adverse environmental conditions. An enclosure ventilation system is keeps temperatures under acceptable limits and dilutes any potentially explosive accumulation of gas due to unexpected leakages. The functional and structural integrity as well as certification needs of the instrumentation and auxiliary systems in the package require that temperatures do not exceed a given threshold. Moreover, accidental fuel gas leakages inside the package must be studied in detail for safety purposes as required by ISO21789. CFD is routinely used in BHGE (Baker Hughes, a GE Company) to assist in the design and verification of the complete enclosure and ventilation system. This may require multiple CFD runs of very complex domains and flow fields in several operating conditions, with a large computational effort. Modeling assumptions and simulation set-up in terms of turbulence and thermal models, and the steady or unsteady nature of the simulations must be carefully assessed. In order to find a good compromise between accuracy and computational effort the present work focuses on the analysis of three different approaches, RANS, URANS and Hybrid-LES. The different computational approaches are first applied to an isothermal scaled-down model for validation purposes where it was possible to determine the impact of the large-scale flow unsteadiness and compare with measurements. Then, the analysis proceeds to a full-scale real aero-derivative gas turbine package. in which the aero and thermal field were investigated by a set of URANS and Hybrid-LES that includes the heat released by the engine. The different approaches are compared by analyzing flow and temperature fields. Finally, an accidental gas leak and the subsequent gas diffusion and/or accumulation inside the package are studied and compared. The outcome of this work highlights how the most suitable approach to be followed for industrial purposes depends on the goal of the CFD study and on the specific scenario, such as NPI Program or RQS Project.

Construction equipment engine performance degradation due to environmental and operation factors in Latin America

2019 ◽  
Vol 25 (3) ◽  
pp. 499-524
Author(s):  
Kurt Azevedo ◽  
Daniel B. Olsen
Keyword(s):  
Operating Conditions ◽  
Mitigation Strategies ◽  
Sensor Data ◽  
Engine Oil ◽  
Construction Equipment ◽  
Base Number ◽  
Oil Viscosity ◽  
Mining Operations ◽  
Content Type ◽  
Engine Wear

Purpose The purpose of this paper is to determine whether the altitude at which construction equipment operates affects or contributes to increased engine wear. Design/methodology/approach The study includes the evaluation of two John Deere PowerTech Plus 6,068 Tier 3 diesel engines, the utilization of OSA3 oil analysis laboratory equipment to analyze oil samples, the employment of standard sampling scope and methods, and the analysis of key Engine Control Unit (ECU) data points (machine utilization, Diagnostic Trouble Codes (DTCs) and engine sensor data). Findings At 250 h of engine oil use, the engine operating at 3,657 meters above sea level (MASL) had considerably more wear than the engine operating at 416 MASL. The leading and earliest indicator of engine wear was a high level of iron particles in the engine oil, reaching abnormal levels at 218 h. The following engine oil contaminants were more prevalent in the engine operating at the higher altitude: potassium, glycol, water and soot. Furthermore, the engine operating at higher altitude also presented abnormal and critical levels of oil viscosity, Total Base Number and oxidation. When comparing the oil sample analysis with the engine ECU data, it was determined that engine idling is a contributor for soot accumulation in the engine operating at the higher altitude. The most prevalent DTCs were water in fuel, extreme low coolant levels and extreme high exhaust manifold temperature. The ECU operating data demonstrated that the higher altitude environment caused the engine to miss-fire and rail pressure was irregular. Practical implications Many of the mining operations and construction projects are accomplished at mid to high altitudes. This research provides a comparison of how construction equipment engines are affected by this type of environment (i.e. higher altitudes, cooler temperatures and lower atmospheric pressure). Consequently, service engineers can implement maintenance strategies to minimize internal engine wear for equipment operating at higher altitudes. Originality/value The main contribution of this paper will help construction equipment end-users, maintenance engineers and manufacturers to implement mitigation strategies to improve engine durability for countries with operating conditions similar to those described in this research.

ENERGY EFFICIENCY OF OPERATING MODES OF MAIN OIL PIPELINES WITH PERIODICAL PARTIAL OIL DUMPING

2018 ◽  
pp. 151-160
Author(s):  
Y. V. Yakymiv ◽  
O. M. Bortnyak
Keyword(s):  
Energy Efficiency ◽  
Transportation Systems ◽  
Operating Conditions ◽  
Oil Pipeline ◽  
Operating Modes ◽  
Oil Transportation ◽  
Pumping Stations ◽  
Oil Pipelines ◽  
Oil Flow ◽  
The Impact

Modern oil transportation systems are characterized by a complex hydraulic structure and geometric configuration, and often require the need for a permanent or periodic pumping or dumping part of the oil flow. The implementation of such transportation technology necessarily leads to changes in the operating conditions of oil pipelines and in accordance with the need to regulate the operation of oil pumping stations. Consequently, determining the patterns of the impact of the process of dumping the part of the oil on the energy parameters of the operation of oil transportation systems is an extremely important task.The influence of periodic dumping the part of oil on the energy efficiency of the operation of main oil pipelines was studied. The impact of volume of discharges on the consumption of power on pumping oil in the system of the main oil pipeline was analyzed. It has been found that with the increase the volume of discharges, the specific consumption of electricity for oil pumping decreases.Based on the carried research, the recommendations on the selection of reliable, safe and optimal pumping modes in terms of cost of electricity for the operation of oil pipelines "Druzhba" in the direction of Mozyr - Brody - Tukholsky pass with periodical partial oil dumping on LPDS "Brody".

Variation of Zero Net Liquid Holdup in a Gas Liquid Cylindrical Cyclone Separator Below Operational Envelope

2020 ◽  
Author(s):  
Malay Jignesh Shah ◽  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Experimental Data ◽  
Water Flow ◽  
Operating Conditions ◽  
Extended Model ◽  
Gas Velocity ◽  
Oil Viscosity ◽  
Liquid Holdup ◽  
Cylindrical Cyclone ◽  
Oil Flow ◽  
Operational Envelope

Abstract Novel experimental and theoretical investigations are carried out on Zero Net Liquid Flow (ZNLF) in the upper part of the Gas-Liquid Cylindrical Cyclone (GLCC©) separator. Experimental data are acquired for the variation of the Zero Net Liquid Holdup (ZNLH) and the associated Churn region height for air-oil and air-water flow. The experiments are carried out at normal operating conditions below the GLCC Operational Envelope (OPEN) for Liquid Carry-Over (LCO). The ZNLH measurements for air-oil flow are higher than those for air-water flow. The Churn region height is higher for air-oil flow, as compared to the air-water flow, for the same operating conditions. The higher oil viscosity, which results in higher frictional and drag forces, leads to greater ZNLH for air-oil flow. The Churn region height is sensitive to the superficial gas velocity, whereby a small increase of gas velocity results in exponential growth of the Churn region height. The model developed by Karpurapu et al. (2018) for predicting the ZNLH at specific operational conditions just below the OPEN for LCO is extended to predict the ZNLH variation along the upper part of the GLCC below the OPEN for LCO, as well as the associated Churn region height. The predictions of the developed extended model for the ZNLH variation compared to the acquired experimental data showing discrepancies of 8% and 3%, respectively, for air-oil and air-water flows.

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