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.

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.

scholarly journals Simulation of the oil supply through the connecting rod to the piston cooling channels in medium speed engines

2020 ◽  
Vol 180 (1) ◽  
pp. 25-30
Author(s):  
Maciej JASKIERNIK ◽  
Konrad BUCZEK ◽  
Jędrzej WALKOWIAK
Keyword(s):  
Compression Ratio ◽  
Flow Simulation ◽  
Engine Oil ◽  
Connecting Rod ◽  
Engine Operation ◽  
Oil Supply ◽  
Cooling Channels ◽  
Medium Speed ◽  
Oil Flow ◽  
Piston Cooling

The importance of the oil flow simulation in connecting rod oil channels during the engine development process is recently increasing. This can be observed either in medium speed engines, where, as one of the traditional solutions, the oil for piston cooling is supplied through the connecting rod, or in automotive engine VCR (variable compression ratio) connecting rods, where engine oil is used to change the compression ratio of the engine. In both cases, precise numerical results are necessary to shorten the prototyping period and to reduce the overall development cost. The multi-physics character of the simulation problem basically consists of the interaction between the dynamics of the crank train components and the oil flow. For the oil supply to the piston cooling channels through the connecting rod in medium speed engines, being the objective of this paper, a major influencing factor is the oil pressure behavior in the piston cooling gallery providing periodical interaction with its supply. At the same time, the connecting rod elastic deformation during engine operation can be regarded as negligible and the planar motion of the connecting rod can be reproduced by combination of translational and rotational acceleration fields in the CFD solver. The paper includes the description of the applied simulation approach, the results and a comparison with the state-of-the art calculation without consideration of the above-mentioned influencing factors.

Thermodynamic Performance of Ice Thermal Energy Storage Systems

2000 ◽  
Vol 122 (4) ◽  
pp. 205-211 ◽  
Author(s):  
Marc A. Rosen ◽  
Ibrahim Dincer ◽  
Norman Pedinelli
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Analysis ◽  
Average Energy ◽  
Cooling Capacity ◽  
Energy And Exergy ◽  
Thermodynamic Performance ◽  
And Performance ◽  
Thermal Energy Storage Systems

The thermodynamic performance of an encapsulated ice thermal energy storage (ITES) system for cooling capacity is assessed using exergy and energy analyses. A full cycle, with charging, storing, and discharging stages, is considered. The results demonstrate how exergy analysis provides a more realistic and meaningful assessment than the more conventional energy analysis of the efficiency and performance of an ITES system. The overall energy and exergy efficiencies are 99.5 and 50.9 percent, respectively. The average exergy efficiencies for the charging, discharging, and storing periods are 86, 60, and over 99 percent, respectively, while the average energy efficiency for each of these periods exceeds 99 percent. These results indicate that energy analysis leads to misleadingly optimistic statements of ITES efficiency. The results should prove useful to engineers and designers seeking to improve and optimize ITES systems. [S0195-0738(00)00904-3]

Numerical treatment of melting heat transfer and entropy generation in stagnation point flow of hybrid nanomaterials (SWCNT-MWCNT/engine oil)

2021 ◽  
Vol 35 (06) ◽  
pp. 2150102
Author(s):  
Ikram Ullah ◽  
Tasawar Hayat ◽  
Ahmed Alsaedi ◽  
Habib M. Fardoun
Keyword(s):  
Velocity Slip ◽  
Engine Oil ◽  
Stretching Cylinder ◽  
Entropy Analysis ◽  
Hybrid Nanomaterials ◽  
Hybrid Nanomaterial ◽  
Order Analysis ◽  
Governing System ◽  
Oil Flow ◽  
Melting Effect

Present attempt inspects the entropy analysis and melting effect in flow of hybrid nanomaterials consisting of CNTs nanoparticles and engine oil Flow is by a stretching cylinder. Formulation is accountable to the viscous dissipation, velocity slip and thermal radiation impacts. In order to estimate the disorder within the thermo-physical frame, second-order analysis has been used. The governing system with the imposed boundary condition is dimensionless via proper variables. Numerical outcomes are expressed graphically and analyzed. Comparison of hybrid nanomaterial, nanomaterials and regular liquid is expressed graphically. Outcomes indicate that the hybrid nanomaterials have great impact throughout the inspection than the ordinary nanomaterials.

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.

A Small Gas Turbine Plant for Cogeneration of Electricity, Thermal and Cooling Thermal Energy With an Absorption Unit

1997 ◽  
Author(s):  
Maurizio De Lucia ◽  
Carlo Lanfranchi ◽  
Antonio Matucci
Keyword(s):  
Gas Turbine ◽  
Thermal Energy ◽  
Operating Conditions ◽  
Hot Water ◽  
Plant Performance ◽  
Cooling Power ◽  
Operating Parameters ◽  
The European Union ◽  
Cogeneration Plant ◽  
Two Stage

A cogeneration plant with a small gas turbine was installed in a pharmaceutical factory and instrumented for acquiring all the values necessary to appraise both its energetic and cost advantages. The plant was designed and built as a demonstrative project under a program for energy use improvement in industry, partially financed by the European Union. The system comprises as its main components: 1) a gas turbine cogeneration plant for production of power and thermal energy under the form of hot water, superheated water, and steam; 2) a two-stage absorption unit, fueled by the steam produced in the cogeneration plant, for production of cooling thermal energy. The plant was provided with an automatized control system for the acquisition of plant operating parameters. The large amount of data thus provided made it possible to compare the new plant, under actual operating conditions, with the previously existing cooling power station with compression units, and with a traditional power plant. This comparative analysis was based on measurements of the plant operating parameters over nine months, and made it possible to compare actual plant performance with that expected and ISO values. The analysis results reveal that gas turbine performance is greatly affected by part-load as well as ambient temperature conditions. Two-stage absorber performance, moreover, turned out to decrease sharply and more than expected in off-design operating conditions.

scholarly journals Operating parameters affecting the thermal performance of biomass boilers

TAPPI Journal ◽  
2017 ◽  
Vol 16 (08) ◽  
pp. 453-461
Author(s):  
Naz Orang ◽  
Honghi Tran ◽  
Andy Jones ◽  
F. Donald Jones
Keyword(s):  
Moisture Content ◽  
Thermal Performance ◽  
Excess Oxygen ◽  
Operating Parameters ◽  
Pulp Mills ◽  
Furnace Temperature ◽  
Bubbling Fluidized Bed ◽  
Oil Flow ◽  
Induced Draft Fan ◽  
Content Range

Operating data of a bubbling fluidized bed (BFB) boiler and three stoker grate (SG) biomass boilers from different pulp mills were analyzed over a 2-year period. The results show that in all cases, the thermal performance decreases markedly from 5.5 to 4 lb steam/lb dry biomass as the feedstock moisture content increases from 40% to 60%. The BFB boiler had better thermal performance, although it operated in a higher moisture content range compared with the SG boilers. Multivariate analysis was also performed on one of the SG boilers to determine operating parameters that affect thermal performance. The results show that furnace temperature, oil flow rate, and induced draft fan current positively correlate with thermal performance, while the feedstock moisture content, total air flow, and excess oxygen (O2) negatively correlate with thermal performance. This implies that when making modifications to improve thermal performance, it is important to take into account correlations among various parameters. In some cases, one positively correlated parameter might cause an increase in a negatively correlated parameter. The net effect might be a decrease in thermal performance.

scholarly journals Calculation algorithm for operating parameters of steam-compressive chilling machine with adsorptive chillling unit

2020 ◽  
Vol 8 (2) ◽  
pp. 3-9
Author(s):  
E.A. Belyanovskaya ◽  
◽  
G.M. Pustovoy ◽  
A.I. Sklyarenko ◽  
M.P. Sukhyy ◽  
...  
Keyword(s):  
Silica Gel ◽  
Thermal Energy ◽  
Sodium Acetate ◽  
Operating Conditions ◽  
Energy Utilization ◽  
Coefficient Of Performance ◽  
Adsorptive Capacity ◽  
Operating Parameters ◽  
Adsorption Refrigeration ◽  
Refrigeration Unit

The work is focused on the development of an effective algorithm for calculating the operational characteristics of a steamcompressive chilling machine with an adsorptive chilling unit, which involves a cold box, an adsorber, an evaporator and a condenser, water being used as a refrigerant. An algorithm for calculating the operating parameters of the adsorptive chilling unit has been developed, which includes the determination of the cooling capacity of the steam compressor refrigeration unit, the heat load on the condenser, the power consumed by the compressor, the coefficient of performance of the steam compressor refrigeration unit, as well as the calculation of the mass of water, the mass of the adsorbent, the refrigerating capacity, the coefficient of performance of the adsorptive chilling unit and the coefficient of useful energy utilization of a steam compressive chilling machine with an adsorption chilling unit. The chilling capacity and the coefficient of performance of the adsorption chilling unit are estimated under the operating conditions of a typical steam compression chilling machine. The crucial factors affecting the efficiency of the adsorptive chilling unit are analyzed. It has been established that the chilling capacity, the coefficient of performance of the adsorption refrigeration module and the energy efficiency of the installation are determined by the thermal load on the condenser, and, therefore, by the mass of water that is desorbed and evaporated. The coefficient of performance of the adsorption chilling unit and the efficiency of the steam compressor chilling machine with the adsorptive chilling unit are estimated to be 0.878 and 4.64. The criteria for the selection of adsorbents for the adsorption module are analyzed. The temperature of regeneration is determined by the temperatures in the condenser, and the limit adsorption affects the mass of the adsorbent and the size of the adsorber. A comparison of the efficiency of adsorptive chi l l ing uni t based on silicoaluminophosphates and composite adsorbents «silica gel – sodium acetate» is carried out. The prospects of using composites «silica gel – СН3СООNa» are shown. The optimal composition of the composite was established, which corresponds to the minimal size of the adsorber, (80% sodium acetate and 20% silica gel). The prospects of using adsorptive conversion of thermal energy for utilization of low-potential thermal energy during the operation of steam compressive chilling machine are shown. Keywords: adsorptive conversion of heat energy, composite adsorbent, steam compressive chilling unit, adsorption, adsorptive capacity.

Performance analysis of a finite noncircular floating ring bearing in turbulent flow regime

2016 ◽  
Vol 231 (7) ◽  
pp. 869-888 ◽  
Author(s):  
Sandeep Soni ◽  
DP Vakharia
Keyword(s):  
Steady State ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Turbulent Regime ◽  
New Variety ◽  
Navier Stokes Equations ◽  
Turbulent Flow Regime ◽  
Oil Flow ◽  
Steady State Performance

The present paper investigates the turbulence effect on the steady-state performance of a new variety of journal bearing, i.e. the noncircular floating ring bearing. This particular bearing consists of the journal, floating ring, as well as lower and upper lobes. The shaft and the floating ring are cylindrical while surfaces of the bearing are noncircular. The classical Navier–Stokes equations and continuity equation in cylindrical coordinates are being satisfactorily adapted with the linearized turbulent lubrication model of Ng and Pan. These improved equations are being solved by the finite element method using Galerkin’s technique and an appropriate iteration strategy. The proposed bearing has a length-to-diameter ratio of 1 and operates over different values of the ratio of clearances (i.e. 0.70 and 1.30). The steady-state performance parameters computed are presented in terms of an inner and outer film eccentricity ratios, load-carrying capacity, attitude angle, speed ratio, friction coefficient variable, oil flow, and temperature rise variable for the Reynolds number up to 9000. The present analysis predicts better performance in the turbulent regime as compared to the laminar regime for the noncircular floating ring bearing.

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