Dynamic Test Bench Research Articles

Influence of decontamination process parameters on ultrasonic decontamination efficiency of pipeline

Many radioactive pollutants will be deposited inside the nuclear power plant pipelines after long-term service, which will form radioactive hot spots and increase the radiation dose rate level of operators. The ultrasonic decontamination efficiency was studied through the establishment of ultrasonic decontamination dynamic test bench, under different decontamination process parameters. It has also been applied in the engineering filed. The results show that: Ultrasonic decontamination efficiency increases with the increase of decontamination power, and the maximum decontamination efficiency of pollutants is up to 62.69%. The main reason is that the mechanical effect and cavitation effect of ultrasonic are significant with the increase of power, which is conducive to the removal of pollutants in the pipeline. When the decontamination time is 60min, the ultrasonic decontamination efficiency is more than 90%. Meanwhile, after ultrasonic decontamination of the pipeline hot spots, the contact dose rate at the pipeline hot spots is reduced by 75.20% at the highest, and the environmental dose rate is reduced by more than 90%, which reduces the collective dose level of operators working near the pipeline hot spot greatly, and ensures the health of the operators and environmental safety.

Turbocompound energy recovery option on a turbocharged diesel engine

The transportation sector is living a transition era in which hybrid and electrified vehicles are replacing conventional vehicles, based on internal combustion engines. This is pushed by the recognized need for reducing fuel consumption and tailpipe emissions, considering primary pollutants and carbon dioxide as a greenhouse gas. In the transition path, hybridization and partial electrification of the powertrain play a crucial role. In this regard, the need for on-board electrical energy storage and utilization is increasing significantly and the possibility to recover wasted energy and convert it into electrical form is mandatory. This is especially true for commercial and heavy-duty vehicles, where full electrification is more difficult to be implemented. Waste Heat Recovery (WHR) has therefore become so important for vehicles, not only to directly reduce fuel consumption and related emissions but also to improve the feasibility of a generation of vehicles with a higher degree of hybridization that considers, for example, the electrification of auxiliaries following the so-called auxiliaries-on-demand management. Wasted heat refers mainly to exhaust heat from gases, where about one third of the fuel energy is disposed of. Among the various systems for WHR, engine turbo-compounding is approaching a mature technology. This technological option makes use of an additional turbine on the exhaust line of the engine, downstream of the turbocharging one, which converts the residual gas enthalpy into mechanical form. In this paper, the F1C Iveco 3.0 L turbocharged diesel engine is considered for verifying the performances of a turbo-compounding system. The engine was mounted on a dynamic engine test bench. In particular, the interactions with the original engine produced on the exhaust line were studied. Backpressure effects on the engine introduced by turbo-compounding were evaluated reversed in terms of extra fuel consumption. Moreover, the new equilibrium of the turbocharger was assessed and the related modifications to the engine were measured considering that the turbocharger has a control strategy based on the so-called Variable Geometry Turbine (VGT), via the modification of the Inlet Guide Vanes (IGV). The presence of a secondary turbine for WHR opens to a wider possibility of actuating the IGV and, so, the possibility to optimize the recovery considering the integrated system and all its degrees of freedom.

The model-based development of a dynamic test bench for testing damper assemblies with a focus on amplitudes with small excitations

The model-based development of a dynamic test bench for testing damper assemblies with a focus on amplitudes with small excitations

Mathematical Modelling and Fluidic Thrust Vectoring Control of a Delta Wing UAV

Pitch control of an unmanned aerial vehicle (UAV) using fluidic thrust vectoring (FTV) is a relatively novel technique requiring no moving control surfaces, such as elevators. In this paper, the authors’ previous work on the characterization of a static co-flow FTV rig is further validated using the free to pitch dynamic test bench. The deflection of a primary jet after injection of a high-velocity secondary jet was captured using the tuft flow visualization technique, along with the experimental recording of subsequent normal force impinged on the Coanda surface resulting in the pitching moment. The effect of primary and secondary flow velocities on exhaust jet deflection, as well as on the pitch angle of the aircraft, is examined. Aerodynamic gain as well as the inertia of a delta wing UAV test bench are computed through experiments and fed into the equation of motion (e.o.m). The e.o.m developed aided in the design of a model-based PID controller for pitch motion control using the multi-parameter root locus technique. The root locus tuned controller serves as a benchmark controller for performance evaluation of the genetic algorithm (GA) and particle swarm optimization (PSO) tuned controllers. Furthermore, the frequency domain metric of gain and phase margins were also employed to reach a robust control design. Experiments conducted in a simulation environment reveal that PSO-PID results in a better response of the UAV in comparison to the baseline pitch controller.

Performance Analysis of a Dynamic Test Bench Based on a Linear Direct Drive

This paper describes the design and performance of a dynamic test bench used for dynamic testing of special sensor systems intended for use in vehicle chassis. In order to economically meet all requirements of a dynamic driving simulation, the dynamic test bench is being developed on the basis of a linear direct drive. The test bench has a modular design and can be used flexibly, i.e. vertically or horizontally. No ferromagnetic material is used in the measuring range of the sensor to minimize measurement inaccuracies. The performance requirements to be met are to the achievable acceleration and frequency, the stroke distance and the positioning accuracy. The test bench must be capable of accelerating at a minimum of 30 g while realizing an oscillation of at least 12 Hz. Regardless of the dynamic requirements, a minimum stroke distance of 500 mm is required. The required positioning accuracy is 1 mm. To ensure that all requirements are met, the performance limits of the test bench are determined experimentally and validated mathematically. In addition to the maximum acceleration and the maximum realizable frequency, the maximum stroke speed of the test rig is determined. Furthermore, the critical resonance frequencies of the test bench, which can lead to disturbances, are determined. As a result, all required performance values are exceeded by the dynamic test bench.

Outlet Pressure and Flow Characteristics of a New Two-Dimensional Piston Pump with an Overlapped Distributor

This article presents the design of a two-dimensional (2D) piston pump flow-distribution port with an overlapped structure that reduces backflow in the pump chamber and pressure ripples at the pump outlet, thus minimizing vibration and noise caused by the high-frequency distribution process of a single two-dimensional (2D) piston pump. We describe the flow distribution structure and operation principle of the 2D pump, create a mathematical model of the pump chamber pressure by using the motion and flow continuity equations of the 2D piston, and use a Matlab program to compile and solve them. The influence of the flow distribution port overlap on the pump chamber pressure and the outlet flow rate was simulated. A prototype was designed and tested on a dynamic performance test bench. Our test bench results show that the flow distribution port overlap can reduce the pressure ripple at the pump outlet, which is consistent with the simulation results.

FEM-based optimal design and testing of synchronous magnetic coupling for aerospace Starter/Generator applications

Improvements in high energy density rare-earth permanent magnets make it innovative to develop magnetic couplings for Starter/Generator applications in the light of more electric aircraft to ensure magnetically insulated contactless power transmission between decoupled shafts for safe operation. Although there are essential studies on magnetic couplings in the literature, especially those for aerospace Starter/Generator structures are rarely encountered. However, methodologies considering system constraints and examining design parameters of couplings are in demand. In response to such a need, this paper proposes the novel design of highly reliable synchronous radial magnetic couplings with torque requirements of 6 and 12 N·m to isolate Starter/Generator and piston engine shafts in model aircraft. The preliminary volume is obtained analytically. Simulations are executed by optimetric approaches in Ansys Maxwell 2D. Optimisation techniques are compared in Maxwell 3D to get the final shape. The retaining sleeve of 0.5 mm is suggested. Loss of synchronisation in the event of the piston shaft failure or exceeding the maximum torque of the coupling is also examined. The torque fluctuation at load changes is 0.1%. Performance tests are conducted on the direct dynamic test bench. Absolute error margin is 37% for the Virtual Work method, 13% for 2D FEM and 6% for 3D FEM. The coupling efficiency is 93.8% at the maximum operating speed and the critical angle, and 96.9% at the minimum torque angle and the minimum operating speed.

Study of Novel Oil-Immersed Torque Motor for Two-Dimensional Valve

The electro-mechanical converters of valves are mostly dry type, which cannot work for a long time under high currents due to heat dissipation. This paper presents a novel oil-immersed torque motor (OTM) that can carry out the 2D motion. The OTM has a separate wet working chamber and heat dissipation structure, and the coil is external to prevent oil contamination from causing short circuits. The equations of motion were established based on the equivalent magnetic circuit (EMC) method and its own characteristics, and the effect of oil damping in the working chamber on the dynamic characteristics of the novel OTM was studied. After analyzing its working principle and dynamic and static characteristics by finite element and numerical analysis software, a prototype was designed and machined, which could be operated in dry and immersed mode by adding parts. In addition, a dynamic and static test bench and a temperature rise test bench were established, and comparison experiments with a conventional dry-type torque motor (CDTM) were conducted. Experimental results showed that the prototype had a good thermal resolution in immersed mode, and when the coil was fully loaded (2.4 A), it still worked in the safe temperature range. The prototype had good current-torque characteristics and hysteresis linearity at a coil magnetomotive force (MMF) of 0–450 A. The output torque could reach 0.7 Nm when MMF exceeds 1000 A. The prototype had an approximately 4% faster step response in immersed mode and about 17.8% wider bandwidth than in dry mode, while the torque motor system was more stable due to the increased damping ratio. The measured open-loop dynamic and static characteristics met the requirements of the electro-mechanical converter of 2D servo valves.

Study on laser de-weight and dynamic balance technology of rotating machines

Abstract To solve the poor precision and low efficiency of manual grinding de-weight dynamic balance of turbopump rotor, the laser de-weight dynamic balance technology of rotating machines is adopted. Combined with the advantages of laser de-weight, such as, fast processing speed high machining precision and good machined surface quality, the smooth transition of the machined surface was realized by means of hierarchical machining. According to the characteristics of the turbopump rotor structure, the equivalent transformation model for laser de-weight turbopump rotor was built to convert the unbalance into laser processing parameters, which achieve the rapid and accurate de-weight of turbopump rotor. It focuses on solving the repeatedly loading and low accuracy of manual grinding dynamic balance. To verify the effectiveness of the proposed technique, laser de-weight experiments were carried out on two turbopump rotor test pieces. A dynamic balance test bench was set up to measure the rotor residual unbalance at 1800 r/min test speed, which is low dynamic balance. The results show that the machined surface transition was smooth, the residual unbalance was small and the machining efficiency was high. The effect of laser de-weight dynamic balance reached the expectation. It is an universal technology which is not limited to the dynamic balance of turbopump rotor, but also applicable to other rotating machinery..

Comparison on the energy absorbed of volumetric and centrifugal pumps for automotive engine cooling

Engine thermal management can reduce significantly CO2 emissions in road vehicles without altering sensibly the engine layout. However, more efficient auxiliaries also participate to fuel consumption saving and, therefore, to CO2 emissions reduction. Typically, centrifugal cooling pumps are adopted as circulating devices, but their efficiency varies highly with rotational speed, wasting energy during real operation despite being optimized at the design point. Instead, volumetric pumps keep a high efficiency also far from it, enhancing the overall engine efficiency. In this paper, the performances of a screw-type volumetric pump have been compared with those of a centrifugal pump considering the same cooling circuit of a mid-size engine for passenger vehicles. Both pumps have been designed to satisfy the cooling flow rate required by the engine during a homologation cycle, while verifying their capability to cool the engine operating at maximum power. Once prototyped, the pumps performance maps have been measured, showing a high Best Efficiency Point for both cases. However, the screw pump has better performance in off-design conditions, being the centrifugal pump efficiency strictly dependent on its rotational speed which significantly changes during a real driving. The comparison of the two pumps has been done by reproducing the WLTC on a dynamic test bench. The rotational speed of the volumetric pump has been adjusted to deliver the same flow rate produced by the centrifugal pump as requested by the engine. Results show that the prototyped screw-type volumetric pump absorbs 21% less energy than the prototyped centrifugal pump, reducing CO2 emissions by 0.28 g/km.

Simulation of energy recovery system of high speed transmission shaft dynamic torque test bench

A hydraulic energy recovery and control system is proposed to solve the energy loss problem of the current vehicle transmission shaft torque test bench. On the basis of the original system, power recovery is realized by parallel hydraulic compensation. PID module is used to control the displacement of piston variable pump and motor respectively to adjust the speed and torque to achieve the established working conditions. The feasibility of the hydraulic system and control scheme is verified by AMEsim-MATLAB software and experiments. The results show that the proposed system can not only adjust the set speed and torque dynamically, but also achieve high power recovery.

Засорение и загрязнение щебеночного балласта при эксплуатации железнодорожного пути

Purpose: Determination of legitimacies of clogging, pollution for broken stone ballast, perceiving vibrodynamic load from a rolling stock, as well as of the ballast life. Methods: Theoretical and empirical research methods are used in the study. Theoretical methods are based on the analysis of known models describing broken stone degradation processes during railway track exploitation, and empirical methods — on the pursued experiments and trials. The identification of the legitimacies for pollutants and clogs accumulation in broken stone ballast was based on the results of dynamic bench tests and laboratory determination of broken stone grain composition removed from ballast layer of exploited railway track with various tonnage workout. The methods of statistical processing of test results and regression analysis were used in the study. Results: According to the statistical processing of test results and laboratory determinations of broken stone grain composition, functional dependencies were established for the accumulation in broken stone ballast of the products of own crushing, abrasive wear as well as of external pollution, depending on broken stone initial physical and mechanical properties, railway track exploitation conditions and the system of its maintenance. Mathematical model for the prediction of broken stone ballast life depending on railway track section exploitation conditions was developed in the study. Practical significance: The results of the study make it possible to prognose broken stone ballast life from the condition of its maximally acceptable pollution and clogging and also to plan reasonably railway track maintenance work.

Design study of dynamic mechanical test bench specimen grips

Abstract The characterization of mechanical properties of materials used in biomedical applications is essential for performance evaluation. In addition to quasi-static tests, dynamic tests extend the range of methods and allow predictions of failure, as well as information on durability. Appropriate specimen grips according to the test sample geometry are crucial for a reliable examination of mechanical testing and therefore valid experimental data. In particular, the investigation of polymers is challenging, as properties show major differences depending on temperature and applied loading rate. This could result in slipping or tearing of samples in the specimen grip area. Numerical simulations of reference grips, as well as alternative custom designs, were performed evaluating damage due to the clamping process and to provide appropriate specimen grips for future dynamic-mechanical investigations of materials with variable properties. Both the results of the numerical simulation and preliminary tests with 3D-printed prototypes show a distinct improvement in specimen clamping. Plastic deformation and local stress peaks were reduced while maintaining the same tightening torque.

Applying 3D X-ray Microscopy to Model Coated Gasoline Particulate Filters under Practical Driving Conditions.

Recent progress in 3D X-ray microscopy allows the analysis of coated gasoline particulate filters on a detailed pore-scale level. However, derivable detailed three-dimensional models for filter simulation are not applicable under transient driving conditions of automotive aftertreatment systems due to their inherent complexity. Here, we present a novel concept to utilize highly resolved 3D X-ray microscopy scans and their quantitative analysis for a macroscopic model of coated gasoline particulate filters intended to be applied in a driving cycle. A previously developed filtration model build on a 1D + 1D flow model on the channel scale of a filter is utilized. Accompanying measurements conducted on a dynamic engine test bench serve as validation for pressure drop and filtration characteristics. With the determined properties from 3D X-ray microscopy, the macroscopic model successfully replicates the measurements. Regarding the filter coating, the reduced porosity and a decrease of medium sized pores relative to an uncoated substrate reduce the filtration efficiency under steady-state as well as transient conditions.

Dynamic Properties of Chain Drive in a Scraper Conveyor under Various Working Conditions

A scraper conveyor is important in coal mining. During operation, its working performance is affected by chain speed fluctuations, terrain fluctuations, and load changes. Thus, evaluating the influence of these factors on the dynamic properties of a scraper conveyor is important. This study first built a dynamic property test bench. Then, the vibration signals of the reducer output shaft were measured under various chain speed, terrain, and load conditions. Finally, the dynamic properties of a scraper conveyor were evaluated by conducting a frequency domain analysis of the measured vibration signals. The results show that the output shaft of the motor, the second shaft, and the second-stage meshing gear of the reducer are sensitive to external factors. Under the terrain conditions of “horizontal + vertical” bending, the middle chute was the most sensitive to the meshing frequency of the sprocket chain. This type of condition had a significant influence on the scraping phenomenon of the scraper and the middle chute. Under various load conditions, the amplitude of each shaft of the reducer decreased, especially the amplitude of the motor output shaft, but the scraping amplitude of the scraper and middle chute greatly increased. This study is of great significance for improving the dynamic properties and structural optimization of scraper conveyors.

Model Based Design, Prototyping and Testing of a Small Size High Speed Electrically Driven Centrifugal Pump

<div class="section abstract"><div class="htmlview paragraph">Within automotive sector, there are several high-performance applications, like, for instance, those referred to racing and motorsport, where cooling needs are usually fulfilled by simple circuits with conventional low-efficiency pumps. The cooling needs in these applications are represented by low flow rates delivered (in the range of 10 - 50 L/min). The operating conditions of these small pumps are usually characterized by very high revolution speeds, which intrinsically cause low efficiency and critical intake phenomena (cavitation) if the design is not specifically optimized to address these concerns.</div><div class="htmlview paragraph">Hence, in this paper a small-size pump operating in the racing sector has been designed using a model-based approach, built and tested having reached both high efficiency (aimed to 50%) and absence of intake operational problems (cavitation). Starting from the specific cooling request (design flow rate equal to 14.0 L/min and pressure rise equal to 2.5 bar), the very limited space available on board oriented the design to an operational revolution speed of 12000 RPM. The interest of this study was to introduce a so high revolution speed in more conventional automotive cooling pumps electrically assisted, keeping high efficiency. In fact, the strong reduction of the size of the pump allows an easy and correct positioning on board.</div><div class="htmlview paragraph">The model-based design was done by a two-steps procedure. The first made use of a 0D model which, catching main physical phenomena of the flow even in simplified form, leads to an optimum geometrical design for the impeller and the volute. A final refinement has been done with a CFD code predicting the off-design performance and limiting cavitation zones. Cavitation, which is one of the most critical issues of high-speed pumps, was completely investigated through a CFD numerical analysis.</div><div class="htmlview paragraph">The pump has been prototyped and tested on a dynamic test bench for pumps, which reproduces homologation cycles and real driving. A good agreement has been reached between theoretical and experimental results, being the mean relative error on pressure rise for all operating point close to 4 %. This model-based procedure opens the way to support the development of electric water pumps for more conventional applications (automotive, light duty engines) in which a redesign will be focused to manage the thermal state of the engine and reduce the energy absorbed during the homologation cycle.</div></div>

A diesel engine air path model with a WG and an ETV for exhaust temperature controller design and embedded control

In this paper a mean value model of a turbocharged diesel engine air path with an electric wastegate (WG) and an exhaust throttle valve (ETV) is presented. The model is designed with regard to system analysis, controller design, and real-time feasibility. That means, care is taken to ensure that the model contains the relevant dynamics on the one hand and that the requirements for computing power and memory (RAM) are kept as low as possible on the other hand. New approaches for modeling the ETV and the exhaust gas temperature are presented. The latter is formulated via an artificial neural network (ANN) computed outside the model. The ANN is integrated into the model in such a way that the differentiation of the model still provides meaningful results for controller design. Thus, this model may also be used for online computation of nonlinear model predictive controllers (MPC) or nonlinear state observers. The parameters of the model are determined using GT-Power simulation data covering the entire working range of the engine. Only measured variables that are also accessible on the engine test bench are used. All optimization problems to be solved within the parameter determination are presented. It is analyzed which sensors are suitable to support the model in an implementation on an electronic control unit (ECU), and the effect without and with sensor correction is shown in a dynamic test bench measurement. Furthermore, the properties of the generated C code are presented, which are the number of mathematical operations, the runtimes, and the stack size. An evaluation of the real time capability is given based on eigenvalue analyses and the properties of the C code .

Simulation evaluation of dynamic characteristic identification accuracy of sliding bearing considering test error

Aiming at the dynamic characteristics test bench of sliding bearings, the dynamic model is established. Based on the forward and inverse dynamic problems of the bearing, a simulation evaluation method for the identification accuracy of the sliding bearing dynamic characteristics is proposed and the algorithm is verified. The identification errors of dynamic characteristic coefficients under different excitation frequencies are analyzed, the sensitivities of single frequency excitation method and dual-frequency excitation method to test error are contrastively analyzed, and the influence laws of dynamic characteristic identification accuracy of sliding bearing are evaluated. Based on which the traditional single frequency excitation method has been improved. The dynamic characteristic test should be carried out respectively in the low frequency range and the high frequency range. The main stiffness and cross damping are the average of two tests, the main damping is the identification value in the high frequency, and the cross stiffness is the identification value in the low frequency. That will effectively reduce the impact of test error. The obtained data and laws could support the improvement of the dynamic characteristics test method of sliding bearings and the confirmation of test parameters, thereby the accuracy of dynamic characteristics identification is improved.

Modeling the Catalytic Performance of Coated Gasoline Particulate Filters under Various Operating Conditions

Coated gasoline particulate filters (cGPFs) can reduce gaseous as well as particulate emissions with the same device. However, their more complex design compared to conventional open monoliths requires accurate models in the development phase. We therefore present a new global kinetic model for cGPFs considering standard three-way catalyst reactions and extend it with the impact of lean–rich cycling, referred to as dithering. Submodels are introduced for the oxygen storage and for the extent of oxidation of the active centers. Therefore, the model captures the enhanced conversion of the catalyst under various dithering as well as steady-state conditions. Several steady-state and transient experiments were conducted on a specially equipped dynamic engine test bench in order to calibrate the approach. The proposed model accurately predicts the tailpipe emissions released in a worldwide harmonized light vehicles test procedure driving cycle that is not part of the original calibration data.

Effects of Side Load Chains of a Combine Harvester on Unbalanced Dynamic Vibrations of Its Threshing Drum

In order to study the influence of the side drive on the balance state of the threshing drum, this paper used the side eccentric load chain drive as the power on the threshing drum dynamic balance test bench. By analyzing the influence of different radial phases, different axial distances, and spiral combinations of the threshing drum on the counterweight, this paper studies the law of the effect of side partial load chain drive on the dynamic balance of the threshing drum and finds that the side chain drive has obvious influence on the unbalance phase of the threshing drum and the change of the axial distance of unbalance has little effect on the equilibrium state of the threshing drum. And from this, a vibration balance method based on the equivalent unbalance of the chain drive is proposed, which can predict and calculate the unbalance of the threshing drum. The unbalance of the threshing drum predicted by this method is smaller than the actual measured unbalance. The maximum error is 32.64% and the minimum error is 4.6%. In the two tests, the predicted unbalance is 1.24 mm/s in amplitude and 270 degrees in phase and amplitude 1.4 mm/s and phase 120 degrees, respectively. The measured unbalance is amplitude 1.587 mm/s and phases 286 degrees. The error between prediction and actual measurement is less than 32.64%, and the unbalance amplitudes that can be reduced by one-time dynamic balance are 0.856 mm/s and 0.674 mm/s, respectively. The research results in this paper provide an effective method for the balance state of the multidrum side chain transmission.