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Records with Subject: Modelling and Simulations
Showing records 1 to 25 of 143. [First] Page: 1 2 3 4 5 Last
Offshore Power Plants Integrating a Wind Farm: Design Optimisation and Techno-Economic Assessment Based on Surrogate Modelling
Luca Riboldi, Lars O. Nord
January 17, 2019 (v1)
Keywords: combined cycle, hybrid system, kriging, multi-objective optimisation, offshore wind, oil and gas
The attempt to reduce the environmental impact of the petroleum sector has been the driver for researching energy efficient solutions to supply energy offshore. An attractive option is to develop innovative energy systems including renewable and conventional sources. The paper investigates the possibility to integrate a wind farm into an offshore combined cycle power plant. The design of such an energy system is a complex task as many, possibly conflicting, requirements have to be satisfied. The large variability of operating conditions due to the intermittent nature of wind and to the different stages of exploitation of an oil field makes it challenging to identify the optimal parameters of the combined cycle and the optimal size of the wind farm. To deal with the issue, an optimisation procedure was developed that was able to consider the performance of the system at a number of relevant off-design conditions in the definition of the optimal design. A surrogate modelling technique wa... [more]
Offshore Power Plants Integrating a Wind Farm: Design Optimisation and Techno-Economic Assessment Based on Surrogate Modelling
Luca Riboldi, Lars O. Nord
January 17, 2019 (v2)
Keywords: combined cycle, hybrid system, kriging, multi-objective optimisation, offshore wind, oil and gas
The paper investigates the possibility to integrate a wind farm into an offshore combined cycle power plant. The models used in the publication are here provided.
Hysteresis Characteristic in the Hump Region of a Pump-Turbine Model
Deyou Li, Hongjie Wang, Jinxia Chen, Torbjørn K. Nielsen, Daqing Qin, Xianzhu Wei
January 7, 2019 (v1)
Keywords: experimental investigation, hump characteristic, hysteresis characteristic, pump turbine
The hump feature is one of the major instabilities in pump-turbines. When pump-turbines operate in the hump region, strong noise and serious fluctuations can be observed, which are harmful to their safe and stable operation and can even destroy the whole unit as well as water conveyance system. In this paper, a low specific speed (nq = 36.1 min−1) pump-turbine model was experimentally investigated. Firstly, the hump characteristic was obtained under 19 mm guide vane opening conditions. More interestingly, when the hump characteristic was measured in two directions (increasing and decreasing the discharge), characteristic hysteresis was found in the hump region. The analysis of performance characteristics reveals that the hump instability is the result of Euler momentum and hydraulic losses, and different Euler momentum and hydraulic losses in the two development processes lead to the hysteresis phenomenon. Then, 12 pressure sensors were mounted in the different parts of the pump-turbin... [more]
Some Models for Determination of Parameters of the Soil Oscillation Law during Blasting Operations
Suzana Lutovac, Dragan Medenica, Branko Gluščević, Rade Tokalić, Čedomir Beljić
January 7, 2019 (v1)
Keywords: blasting, oscillation velocity, seismic effect, soil oscillation law, working environment
In order to evaluate and control the seismic effect of blasting, as well as its planning, it is required to determine the soil oscillation law, with the strike/mining facilities to be protected. One of the most commonly used equations is that of M.A. Sadovskii, defining the law of alteration in the oscillation velocity of the soil depending on distance, the explosive amount, and conditions of blasting and geologic characteristics of the soil; all of this being determined on the basis of test blasting for the specific work environment. In the Sadovskii equation two parameters, K and n appear and they are conditioned both by rock mass characteristics and blasting conditions. The practical part of this study includes experimental investigations performed in the Veliki Krivelj Open Pit in the Bor District located in Eastern Serbia and investigations carried out during mass mining in the Kovilovača Open Pit near Despotovac, Eastern Serbia. Thus this paper offers several modes for determinat... [more]
Numerical Study of the Aerodynamic Loads on Offshore Wind Turbines under Typhoon with Full Wind Direction
Jijian Lian, Yaya Jia, Haijun Wang, Fang Liu
January 7, 2019 (v1)
Keywords: aerodynamic load, boundary layer separation, computational fluid dynamics (CFD), full wind direction, parking position, typhoon, wind turbine
Super typhoon activity is likely to make the electric power network fail, or blow the wind-measuring device off, which all lead to the yaw control system of wind turbine being inactive. Under this condition, blades can be blown by the violent side wind from unfavorable directions, and the aerodynamic loads on the wind turbine will be increased by a large amount, which can lead to low-cycle fatigue damage and other catastrophic collapses. So far, not enough consideration has been given to the above problems in wind turbine design. Using the transient computational fluid dynamics (CFD), this study investigates the wind load characteristics of offshore wind turbines under typhoon condition with 360-degree full wind directions. Two primary influence factors of the aerodynamic characteristics of wind turbines are clarified: variation of the wind direction and different parking positions of the wind rotor. Using 3D-numerical simulation results, this study provides detailed references for the... [more]
A Study of an Effective Heat-Dissipating Piezoelectric Fan for High Heat Density Devices
Chien-Nan Lin, Jiin-Yuh Jang, Jin-Sheng Leu
January 7, 2019 (v1)
Keywords: computational fluid dynamics (CFD), energy saving, piezoelectric fan, transient numerical simulation, vibrating cantilever
Heat dissipation per unit volume has grown rapidly, as the size of modern electronic devices has continued to decrease. The air flow induced by an oscillating cantilever blade enhances the heat transfer performance of high heat density devices. The heat transfer improvement mainly depends on the velocity magnitude and distribution of air streams induced by the vibrating blade. Accordingly, this study numerically and experimentally examines the time-varying flow characteristics of a vibrating cantilever for five blade types. The blades are rectangular or trapezoidal with various widths and actuated at various frequencies. The fluid domain is numerically discretized using a dynamic meshing scheme to model the three-dimensional time-varying vibrating blade. The experiment utilizes nine hot-wire velocity meters to measure the average velocities. The flow structure with streamlines and velocity contours of the induced air flow are determined at various section planes. The results show that... [more]
Experimental and Numerical Analyses on the Rotary Vane Expander Operating Conditions in a Micro Organic Rankine Cycle System
Piotr Kolasiński, Przemysław Błasiak, Józef Rak
January 7, 2019 (v1)
Keywords: domestic energy conversion system, numerical modelling, organic Rankine cycle (ORC), rotary vane expander
Micro (0.5⁻10 kW) organic Rankine cycle (ORC) power systems are nowadays considered for domestic power generation. Selection of a suitable expander is one of the most important problems connected with the domestic ORC system design. Volumetric machines or micro-turbines can be adopted as an expander in domestic ORC systems. Scroll and screw expanders are a common choice and were successfully applied in different small- and micro-power applications. However, micro-turbines as well as scroll and screw expanders are mechanically complicated and expensive. An alternative are rotary-vane machines, which are simple and cheap compared to micro-turbines. This paper documents a study providing the experimental and numerical analyses on the rotary vane expander operating conditions in a micro-ORC system. A test-stand was designed and set up and a series of experiments was performed using the test-stand. Results of these experiments were further used as an input to numerical simulations of an exp... [more]
Dynamic Prediction of Power Storage and Delivery by Data-Based Fractional Differential Models of a Lithium Iron Phosphate Battery
Yunfeng Jiang, Xin Zhao, Amir Valibeygi, Raymond A. de Callafon
January 7, 2019 (v1)
Keywords: battery management system (BMS), energy storage and delivery, fractional differential model (FDM), least squares-based state-variable filter (LSSVF) method, system identification
A fractional derivative system identification approach for modeling battery dynamics is presented in this paper, where fractional derivatives are applied to approximate non-linear dynamic behavior of a battery system. The least squares-based state-variable filter (LSSVF) method commonly used in the identification of continuous-time models is extended to allow the estimation of fractional derivative coefficents and parameters of the battery models by monitoring a charge/discharge demand signal and a power storage/delivery signal. In particular, the model is combined by individual fractional differential models (FDMs), where the parameters can be estimated by a least-squares algorithm. Based on experimental data, it is illustrated how the fractional derivative model can be utilized to predict the dynamics of the energy storage and delivery of a lithium iron phosphate battery (LiFePO 4 ) in real-time. The results indicate that a FDM can accurately capture the dynamics of the energy... [more]
Numerical Investigation of Aerodynamic Performance and Loads of a Novel Dual Rotor Wind Turbine
Behnam Moghadassian, Aaron Rosenberg, Anupam Sharma
January 7, 2019 (v1)
Keywords: aerodynamic loads, atmospheric boundary layer, dual-rotor wind turbines, momentum entrainment
The objective of this paper is to numerically investigate the effects of the atmospheric boundary layer on the aerodynamic performance and loads of a novel dual-rotor wind turbine (DRWT). Large eddy simulations are carried out with the turbines operating in the atmospheric boundary layer (ABL) and in a uniform inflow. Two stability conditions corresponding to neutral and slightly stable atmospheres are investigated. The turbines are modeled using the actuator line method where the rotor blades are modeled as body forces. Comparisons are drawn between the DRWT and a comparable conventional single-rotor wind turbine (SRWT) to assess changes in aerodynamic efficiency and loads, as well as wake mixing and momentum and kinetic energy entrainment into the turbine wake layer. The results show that the DRWT improves isolated turbine aerodynamic performance by about 5%⁻6%. The DRWT also enhances turbulent axial momentum entrainment by about 3.3 %. The highest entrainment is observed in t... [more]
New Electro-Thermal Battery Pack Model of an Electric Vehicle
Muhammed Alhanouti, Martin Gießler, Thomas Blank, Frank Gauterin
January 7, 2019 (v1)
Keywords: battery circuit model, electric vehicle, new OCV model, synthesized battery model, temperature influence, thermal model
Since the evolution of the electric and hybrid vehicle, the analysis of batteries’ characteristics and influence on driving range has become essential. This fact advocates the necessity of accurate simulation modeling for batteries. Different models for the Li-ion battery cell are reviewed in this paper and a group of the highly dynamic models is selected for comparison. A new open circuit voltage (OCV) model is proposed. The new model can simulate the OCV curves of lithium iron magnesium phosphate (LiFeMgPO₄) battery type at different temperatures. It also considers both charging and discharging cases. The most remarkable features from different models, in addition to the proposed OCV model, are integrated in a single hybrid electrical model. A lumped thermal model is implemented to simulate the temperature development in the battery cell. The synthesized electro-thermal battery cell model is extended to model a battery pack of an actual electric vehicle. Experimental tests on the bat... [more]
Novel Parametric Circuit Modeling for Li-Ion Batteries
Ximing Cheng, Liguang Yao, Yinjiao Xing, Michael Pecht
January 7, 2019 (v1)
Keywords: equivalent electrical circuit, Li-ion battery, model parameterization, non-negative least squares
Because of their simplicity and dynamic response, current pulse series are often used to extract parameters for equivalent electrical circuit modeling of Li-ion batteries. These models are then applied for performance simulation, state estimation, and thermal analysis in electric vehicles. However, these methods have two problems: The assumption of linear dependence of the matrix columns and negative parameters estimated from discrete-time equations and least-squares methods. In this paper, continuous-time equations are exploited to construct a linearly independent data matrix and parameterize the circuit model by the combination of non-negative least squares and genetic algorithm, which constrains the model parameters to be positive. Trigonometric functions are then developed to fit the parameter curves. The developed model parameterization methodology was applied and assessed by a standard driving cycle.
Numerical Analysis of the Transient Behaviour of a Variable Speed Pump-Turbine during a Pumping Power Reduction Scenario
Giorgio Pavesi, Giovanna Cavazzini, Guido Ardizzon
January 7, 2019 (v1)
Keywords: adjustable speed hydro plants, dynamic response of hydro plants, hydro plant control, pump-turbine
To achieve the carbon free electricity generation target for 2050, the penetration of renewable energy sources should further increase. To address the impacts of their unpredictable and intermittent characteristics on the future electricity grid, Pumped Hydro Energy Storage (PHES) plants should enhance their regulation capability by extending their continuous operating range far beyond the optimal normal working range. However, for the time being, the regulation capability of the new generation of PHES, equipped with reversible pump-turbines due to their cost-effectiveness, is limited at part load by instability problems. The aim of this paper is to analyse, during a pumping power reduction scenario, the onset and development of unsteady phenomena leading to unstable behaviour. A 3D transient numerical simulation was carried out on the first stage of a variable-speed two-stage pump-turbine from full load to the unstable operating zone by progressively reducing the speed from 100% to 88... [more]
Numerical Simulation of the Propagation of Hydraulic and Natural Fracture Using Dijkstra’s Algorithm
Yanfang Wu, Xiao Li
January 7, 2019 (v1)
Keywords: Dijkstra’s algorithm, discrete fracture network, hydraulic fracture, hydraulic fracturing
Utilization of hydraulic-fracturing technology is dramatically increasing in exploitation of natural gas extraction. However the prediction of the configuration of propagated hydraulic fracture is extremely challenging. This paper presents a numerical method of obtaining the configuration of the propagated hydraulic fracture into discrete natural fracture network system. The method is developed on the basis of weighted fracture which is derived in combination of Dijkstra’s algorithm energy theory and vector method. Numerical results along with experimental data demonstrated that proposed method is capable of predicting the propagated hydraulic fracture configuration reasonably with high computation efficiency. Sensitivity analysis reveals a number of interesting observation results: the shortest path weight value decreases with increasing of fracture density and length, and increases with increasing of the angle between fractures to the maximum principal stress direction. Our method is... [more]
Application of Scaling-Law and CFD Modeling to Hydrodynamics of Circulating Biomass Fluidized Bed Gasifier
Mazda Biglari, Hui Liu, Ali Elkamel, Ali Lohi
January 7, 2019 (v1)
Keywords: computation fluid dynamics, fluidized bed, scaling-law
Two modeling approaches, the scaling-law and CFD (Computational Fluid Dynamics) approaches, are presented in this paper. To save on experimental cost of the pilot plant, the scaling-law approach as a low-computational-cost method was adopted and a small scale column operating under ambient temperature and pressure was built. A series of laboratory tests and computer simulations were carried out to evaluate the hydrodynamic characteristics of a pilot fluidized-bed biomass gasifier. In the small scale column solids were fluidized. The pressure and other hydrodynamic properties were monitored for the validation of the scaling-law application. In addition to the scaling-law modeling method, the CFD approach was presented to simulate the gas-particle system in the small column. 2D CFD models were developed to simulate the hydrodynamic regime. The simulation results were validated with the experimental data from the small column. It was proved that the CFD model was able to accurately predic... [more]
Correction: Yang, W.; Yang, J.; Guo, W.; Zeng, W.; Wang, C.; Saarinen, L.; Norrlund, P. A Mathematical Model and Its Application for Hydro Power Units under Different Operating Conditions. Energies 2015, 8, 10260⁻10275
Weijia Yang, Jiandong Yang, Wencheng Guo, Wei Zeng, Chao Wang, Linn Saarinen, Per Norrlund
November 28, 2018 (v1)
The authors wish to make the following corrections to the published paper [1].[...]
A Parameter Identification Method for Dynamics of Lithium Iron Phosphate Batteries Based on Step-Change Current Curves and Constant Current Curves
Zhichao He, Geng Yang, Languang Lu
November 28, 2018 (v1)
Keywords: constant current curves, decouple, parameter identification, step-change current curves
Parameterization of battery dynamics based on terminal operating data is a main concern in engineering applications of batteries. The key technology is designing an adequate test procedure and a data processing procedure to excite different inner dynamics and then estimate the parameters of a corresponding equivalent circuit model (ECM). This paper proposes a parameter identification method that utilizes the terminal voltage curves (TVC) under step-change current conditions and constant current conditions. With this method, I-V characteristics of battery’s Ohmic resistance, mass diffusion process, thermal process and SOC varying process are decoupled and parametric functions of an ECM are obtained. Experimental results show that the method is easy to be implemented and modeling accuracy is sufficient for applications.
Thermo-Structural Response Caused by Structure Gap and Gap Design for Solid Rocket Motor Nozzles
Lin Sun, Futing Bao, Ning Zhang, Weihua Hui, Shaozeng Wang, Nan Zhang, Heng Deng
November 28, 2018 (v1)
Keywords: frictional interfaces, gap design, structure gap, thermo-structural
The thermo-structural response of solid rocket motor nozzles is widely investigated in the design of modern rockets, and many factors related to the material properties have been considered. However, little work has been done to evaluate the effects of structure gaps on the generation of flame leaks. In this paper, a numerical simulation was performed by the finite element method to study the thermo-structural response of a typical nozzle with consideration of the structure gap. Initial boundary conditions for thermo-structural simulation were defined by a quasi-1D model, and then coupled simulations of different gap size matching modes were conducted. It was found that frictional interface treatment could efficiently reduce the stress level. Based on the defined flame leak criteria, gap size optimization was carried out, and the best gap matching mode was determined for designing the nozzle. Testing experiment indicated that the simulation results from the proposed method agreed well... [more]
A Criterion for Rating the Usability and Accuracy of the One-Diode Models for Photovoltaic Modules
Aldo Orioli, Alessandra Di Gangi
November 28, 2018 (v1)
Keywords: five-parameter model, I-V characteristics, one-diode equivalent circuit, photovoltaic modules, solar energy
In selecting a mathematical model for simulating physical behaviours, it is important to reach an acceptable compromise between analytical complexity and achievable precision. With the aim of helping researchers and designers working in the area of photovoltaic systems to make a choice among the numerous diode-based models, a criterion for rating both the usability and accuracy of one-diode models is proposed in this paper. A three-level rating scale, which considers the ease of finding the data used by the analytical procedure, the simplicity of the mathematical tools needed to perform calculations and the accuracy achieved in calculating the current and power, is used. The proposed criterion is tested on some one-diode equivalent circuits whose analytical procedures, hypotheses and equations are minutely reviewed along with the operative steps to calculate the model parameters. To assess the achievable accuracy, the current-voltage (I-V) curves at constant solar irradiance and/or cel... [more]
Three-Dimensional Finite-Element Analysis of the Short-Time and Peak Withstand Current Tests in Substation Connectors
Francesca Capelli, Jordi-Roger Riba, Joan Pérez
November 28, 2018 (v1)
Keywords: connector, finite element method, peak withstand current test, short-time withstand current test, Simulation, substation
Power devices intended for high-voltage systems must be tested according to international standards, which includes the short-time withstand current test and peak withstand current test. However, these tests require very special facilities which consume huge amounts of electrical power. Therefore, mathematical tools to simulate such tests are highly appealing since they allow reproducing the electromagnetic and thermal behavior of the test object in a fast and economical manner. In this paper, a three-dimensional finite element method (3D-FEM) approach to simulate the transient thermal behavior of substation connectors is presented and validated against experimental data. To this end, a multiphysics 3D-FEM method is proposed, which considers both the connector and the reference power conductors. The transient and steady-state temperature profiles of both the conductors and connector provided by the 3D-FEM method prove its suitability and accuracy as compared to experimental data provid... [more]
CFD Analysis on the Thermal Hydraulic Performance of an SAH Duct with Multi V-Shape Roughened Ribs
Anil Kumar, Man-Hoe Kim
November 28, 2018 (v1)
Keywords: heat transfer enhancement, SAH, solar energy, thermal hydraulic performance
This study presents the heat transfer and fluid flow characteristics in a rib-roughened SAH (solar air heater) channel. The artificial roughness of the rectangular channel was in the form of a thin circular wire in discrete multi V-pattern rib geometries. The effect of this geometry on heat transfer, fluid flow, and performance augmentation was investigated using the CFD (computational fluid dynamics). The roughness parameters were a relative discrete distance of 0.69, a relative rib height of 0.043, a relative rib pitch of 10, a relative rib width of 6.0, and a flow-attack-angle of 60°. The discrete width ratios and Reynolds numbers ranged from 0.5 to 2.0 and from 2000 to 20,000, respectively. The CFD results using the renormalization k-epsilon model were in good agreement with the empirical relationship. This model was used to investigate the heat transfer and fluid flow characteristics in the multi V-pattern rib roughened SAH channel. The thermo-hydraulic performance was found to be... [more]
Numerical Modeling of Variable Fluid Injection-Rate Modes on Fracturing Network Evolution in Naturally Fractured Formations
Yu Wang, Xiao Li, Bo Zhang
November 28, 2018 (v1)
Keywords: hydraulic fracturing, hydraulic fracturing effectiveness, numerical simulation, variable injection-rate technology
In this study, variable injection-rate technology was numerically investigated in a pre-existing discrete fracture network (DFN) formation, the Tarim Basin in China. A flow-stress-damage (FSD) coupling model has been used in an initial attempt towards how reservoir response to variable injection-rates at different hydraulic fracturing stages. The established numerical model simultaneously considered the macroscopic and microscopic heterogeneity characteristics. Eight numerical cases were studied. Four cases were used to study the variable injection-rate technology, and the other four cases were applied for a constant injection-rate in order to compare with the variable injection-rate technology. The simulation results show that the variable injection-rate technology is a potentially good method to a form complex fracturing networks. The hydraulic fracturing effectiveness when increasing the injection-rate at each stage is the best, also, the total injected fluid is at a minimum. At the... [more]
Analytical Model for Voltage-Dependent Photo and Dark Currents in Bulk Heterojunction Organic Solar Cells
Mesbahus Saleheen, Salman M. Arnab, M. Z. Kabir
November 28, 2018 (v1)
Keywords: analytical model, charge collection, current-voltage characteristics, dark current, organic solar cells, trapping/recombination
A physics-based explicit mathematical model for the external voltage-dependent forward dark current in bulk heterojunction (BHJ) organic solar cells is developed by considering Shockley-Read-Hall (SRH) recombination and solving the continuity equations for both electrons and holes. An analytical model for the external voltage-dependent photocurrent in BHJ organic solar cells is also proposed by incorporating exponential photon absorption, dissociation efficiency of bound electron-hole pairs (EHPs), carrier trapping, and carrier drift and diffusion in the photon absorption layer. Modified Braun’s model is used to compute the electric field-dependent dissociation efficiency of the bound EHPs. The overall net current is calculated considering the actual solar spectrum. The mathematical models are verified by comparing the model calculations with various published experimental results. We analyze the effects of the contact properties, blend compositions, charge carrier transport properties... [more]
Torque Ripple Reduction of a Novel Modular Arc-Linear Flux-Switching Permanent-Magnet Motor with Rotor Step Skewing
Xiangdong Liu, Zhongxin Gu, Jing Zhao
November 28, 2018 (v1)
Keywords: cogging torque, finite element method (FEM), harmonics, modular arc-linear flux-switching permanent-magnet motor (MAL-FSPM), period ratio of cogging torque to back electromotive force (EMF), rotor step skewing, torque ripple
A novel modular arc-linear flux-switching permanent-magnet motor (MAL-FSPM) used for scanning system instead of reduction gearboxes and kinematic mechanisms is proposed and researched in this paper by the finite element method (FEM). The MAL-FSPM combines characteristics of flux-switching permanent-magnet motor and linear motor and can realize the direct driving and limited angular movement. Structure and operation principle of the MAL-FSPM are analyzed. Cogging torque model of the MAL-FSPM is established. The characteristics of cogging torque and torque ripple are investigated for: (1) distance (dend) between left end of rotor and left end of stator is more than two rotor tooth pitch (τp); and (2) dend is less than two rotor tooth pitch. Cogging torque is an important component of torque ripple and the period ratio of the cogging torque to the back electromotive force (EMF) equals one for the MAL-FSPM before optimization. In order to reduce the torque ripple as much as possible and af... [more]
Numerical Study of Solidification in a Plate Heat Exchange Device with a Zigzag Configuration Containing Multiple Phase-Change-Materials
Peilun Wang, Dacheng Li, Yun Huang, Xingang Zheng, Yi Wang, Zhijian Peng, Yulong Ding
November 28, 2018 (v1)
Keywords: heat exchange, multiple phase-change-materials (m-PCMs), numerical modelling, Process Intensification, solidification, zigzag configuration
Latent heat thermal energy storage (TES) plays an important role in the advocation of TES in contrast to sensible energy storage because of the large storage energy densities per unit mass/volume possible at a nearly constant thermal energy. In the current study, a heat exchange device with a zigzag configuration containing multiple phase-change-materials (m-PCMs) was considered, and an experimental system was built to validate the model for a single PCM. A two-dimensional numerical model was developed using the ANSYS Fluent 14.0 software program. The energy fractions method was put forward to calculate the average Ste number and the influence of Re and Ste numbers on the discharge process were studied. The influence of phase change temperature among m-PCMs on the solidification process has also been studied. A new boundary condition was defined to determine the combined effect of the Re and Ste numbers on the discharging process. The modelling results show that for a given input power... [more]
Modelling, Testing and Analysis of a Regenerative Hydraulic Shock Absorber System
Ruichen Wang, Fengshou Gu, Robert Cattley, Andrew D. Ball
November 27, 2018 (v1)
Keywords: Modelling, parameter identification, power regeneration, shock absorber, suspension
To improve vehicle fuel economy whilst enhancing road handling and ride comfort, power generating suspension systems have recently attracted increased attention in automotive engineering. This paper presents our study of a regenerative hydraulic shock absorber system which converts the oscillatory motion of a vehicle suspension into unidirectional rotary motion of a generator. Firstly a model which takes into account the influences of the dynamics of hydraulic flow, rotational motion and power regeneration is developed. Thereafter the model parameters of fluid bulk modulus, motor efficiencies, viscous friction torque, and voltage and torque constant coefficients are determined based on modelling and experimental studies of a prototype system. The model is then validated under different input excitations and load resistances, obtaining results which show good agreement between prediction and measurement. In particular, the system using piston-rod dimensions of 50⁻30 mm achieves recovera... [more]
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