Experimental Bench Research Articles

Study on Cavitation Noise Monitoring and Characteristics Based on Venturi Bench Test

Cavitation phenomena are accompanied by harsh cavitation noise. Studying cavitation noise is an effective method to monitor cavitation conditions. In order to study the characteristics of cavitation noise, a Venturi test bench experiment platform is built, the cavitation flow field and cavitation noise of Venturi test bench are simulated. The frequency domain analysis of cavitation noise is carried out, and the relationship between cavitation region, flow rate and sound pressure level of cavitation noise is verified by comparison between simulation and experiment. Because the cavitation noise is easily polluted by ambient noise, wavelet transform is used to analyze the cavitation noise and background noise, and the characteristics of cavitation noise are studied by comparing the difference between them.

Research on the Mechanism of the Skidding Device of Bulk Grain into Silo

In the field of handling, storage and transportation, chutes are used to transfer bulk solids between conveyors and warehouses. In these systems, traditional analytical methods based on the principles of continuum mechanics approximate an accelerated flow that contains the physical body solid properties obtained from standardized tests. Because it is difficult to physically observe the flow inside the transfer structure, there have been few studies to validate the method at full scale. In contrast, discrete element modeling (DEM) allows flow visualization through a transfer chute and qualitative and quantitative analysis if accurate simulation parameters are selected. In order to adapt to the needs of modern intelligent warehousing, we reduced the grain crushing and damage in the process of grain storage. To design and investigate the motion performance of grain particles in a sliding dustpan, this paper utilizes rocky simulation technology, combined with the corresponding bench experiments, to study the impact of the angle arrangement of the dustpan, and to verify the results of the simulation analysis based on the stress–strain analysis of the particle impact. It was found that when the angle of the dustpan arrangement was 40 degrees, the flow of all particles had a better performance in terms of pass ability and energy loss. In the continuous cycle obtained from the simulation, the particle group state at each moment is almost the same as the particle characteristics in the experiment, indicating that the angle of the bucket has an effect on the particle permeability. In this paper, the results of the study on the state of the grain group on the silo device will provide a useful reference for the design of a grain silo device.

Fuel Consumption of Adaptive Cruise Control Platoons: Bench Experiments and Data-Driven Estimation for Real Traffic

Fuel Consumption of Adaptive Cruise Control Platoons: Bench Experiments and Data-Driven Estimation for Real Traffic

High-dynamic steering control of the pump-controlled electro-hydraulic steering system for heavy vehicles with active disturbance suppression

Low-frequency response, strong nonlinearity and unknown disturbances are the main challenges faced by the engineering application of the pump-controlled electro-hydraulic steering systems (EHSSs) for heavy vehicles. To solve the above problems, an active disturbance suppression controller is proposed based on a variable rate reaching law (VRRL) and a terminal sliding mode observer (TSMO) in the framework of the sliding mode control. This controller is unique because, the VRRL introduces a nonlinear activation function, which enables smooth switching between multiple reaching rates, effectively improving the response speed and the disturbance rejection performance of the pump-controlled EHSS. Furthermore, an adaptive incomplete disturbance compensation control strategy is proposed by incorporating a TSMO to further improve the accuracy and robustness of the steering system, which employs a VRRL-based TSMO to realize accurate estimation of the lumped disturbance in finite time, and avoids controller overcompensation by selecting a preferred disturbance compensation coefficient. The stability analysis demonstrates that the proposed controller effectively suppresses the lumped disturbance and reduces the convergence domain of the steering system. A pump-controlled EHSS experimental bench is constructed, and a series of experiments are conducted with various steering frequencies and load conditions, which validate the ability of the proposed controller to achieve high-precision dynamic steering in all-terrain conditions of the pump-controlled EHSS for heavy vehicles.

Thermo-Acoustic Properties of Four Natural Fibers, Musa textilis, Furcraea andina, Cocos nucifera, and Schoenoplectus californicus, for Building Applications

Natural and bio-based construction materials such as bamboo, cork, or natural fiber composites offer a promising solution for enhancing the environmental sustainability of buildings. In this sense, the paper presents an experimental thermo-acoustic characterization of four common Ecuadorian natural fibers, abaca (Musa textilis), cabuya (Furcraea andina), coir (Cocos nucifera), and totora (Schoenoplectus californicus). Different densities were considered, from 85 kg/m3 (Cabuya) to 244 kg/m3 (totora), to thermo-acoustically characterize the samples built with these fibers, by means of the guarded-hot-plate (GHP) and impedance tube methods in-lab experimental benches. The exhaustive original characterization of the evaluated natural fiber composites showed a promising overall thermo-acoustic behavior. The thermal conductivity of the fibers was around 0.04–0.06 W/m·K and, therefore, comparable to other materials such as polystyrene, polyurethane, or aerogel that are already utilized for similar applications. On the other hand, the sound-absorption properties of the evaluated fibers are also very competitive, but strongly affected by the thickness of the sample, with noise reduction coefficient NRC ranging from 0.12 to 0.53. Consequently, the production and distribution of these materials in the Ecuadorian market for thermal insulation and acoustic conditioning constitute an alternative characterized by good technical performance, which, compared to synthetic composites used in the construction industry for similar duties, is ecological, sustainable, and has low built-in energy consumption.

Effect of tilt angle and base plate design on the performance of a loop heat pipe driven by vapor–liquid injector

With the rapid development of microelectronics technology and the increasing heat flux of electronic devices, loop heat pipes have garnered significant attention for their highly efficient passive heat transfer performance. However, the heat transfer performance of conventional loop heat pipes is impaired by the heat leakage, and the maximum heat flux is unable to meet the heat dissipation requirement of high-heat-flux devices. To solve this problem, a loop heat pipe with a vapor-driven injector (LHPI) was previously proposed. However, only the heat transfer performance of the horizontally-placed LHPI had been investigated in the preliminary stage, and the effect of gravity on the heat transfer performance was not further discussed. Now in this paper, a 360° rotatable experimental bench is designed to investigate the influence of the tilt angle on the performance of LHPI. In addition, a capillary wick is integrally sintered with the trough baseplate and the microcolumn baseplate of the LHPI, respectively, to reduce the thermal resistance between them. The results show that the heat transfer performance of LHPI is significantly affected by its tilt angle. In the horizontal condition, LHPI exhibits the lowest baseplate temperature and thermal resistance, and the best heat transfer performance, which verifies its applications in engineering. Integral sintering increases the maximum thermal load from 300 W to 350 W under stable operation conditions of LHPI. The maximum thermal load of the integrated micro pin-finned baseplate reaches 500 W, which improves the heat dissipation effect by 42 % in heat dissipation compared to the trough baseplate under the same conditions., providing an improvement angle for the traditional LHP.

Study of piston offset inhibition method based on the biased center port

The linear compressor is one of the main energy-consuming components in domestic and space refrigeration systems. Due to the asymmetric leakage in the clearance, the piston offset unavoidably causes the piston to deviate from its designed equilibrium position and worsens the compressor performance. In this paper, a new method is proposed to inhibit the piston offset. A biased center port is employed to direct gas from the back chamber to the front at the position close to the back chamber to balance the pressure on the two sides of the piston. To verify this method, a numerical simulation was performed to calculate the mass flow through the clearance and center port channel, and the average pressure difference across the piston. An experimental bench was established to compare the offset of the structures with no center port, unbiased center port and biased center port. Results show that the biased center port can almost eliminate the piston offset at the designed operating condition.

Development of a new environmentally friendly and efficient centrifugal variable diameter metering device.

The design of the maize metering device involves centrifugal variable diameter pneumatic and cleaning mechanisms, aiming to enhance the performance and power efficiency of pneumatic maize metering devices. Leveraging the impact of changes in centrifugal diameter and the guidance and positioning of airflow, we optimize the hole insert, seeding plate, seed limit board, and integrated front shell. This optimization facilitates the adjustment of both the quantity and posture of seed filling. As a result, seeds can form a uniform flow within the annular cavity, reducing the wind pressure necessary for regular operation and decreasing power consumption. A quadratic regression orthogonal rotation combination experiment is conducted using a self-made experiment bench, considering ground speed, wind pressure, and seeding rate as the experiment factors. Furthermore, a comparative experiment involving a novel centrifugal variable-diameter type metering device. The results indicate optimal seeding performance when the ground speed is 13.2 km/h, the wind pressure is 1.2 kPa, and the feeding rate is 25 seeds/s. Under these conditions, the quality of feed index reaches 95.20%, the multi-index is 3.87%, and the miss index is 0.93%. Findings reveal that the developed seed metering device achieved a quality of feed index exceeding 93.00% across varying speeds of 12~18 km/h, aligning with the production requirements. Moreover, the actual power consumption of Type B and C is about 85.00% and 98.00% lower than Type A, standing at only 32.90 W at 18 km/h. The COP of Type C is about 86 times and 12 times that of Type A and B, respectively, meeting the demands for efficient production of maize seed metering devices. In comparison to traditional design and structural parameter optimization methods for maize seed metering device, this study is helpful to the sustainable development of maize industry and reduce environmental pollution.

Recent Patents on Closed Coal Storage Systems and Research of Similar Experimental

Background:: Coal storage and conveying are key aspects of the coal industry, including coal stacking management systems and conveying systems. The traditional method of coal storage will easily lead to coal’s spontaneous combustion, which decreases the safety and reliability of storage. Meanwhile, problems are waiting to be solved with current conveying technologies, such as low levels of conveying efficiency. Objective:: To enhance the efficiency of coal conveying while improving safety and reducing environmental pollution, and promote the application of closed coal storage systems and pneumatic conveying technology. Method:: The patents and research proposed by many scholars analyzed the problems in coal transportation. Adopting pneumatic conveying technology and utilizing a similar experimental bench, by controlling the angle of the suction feeder and the height from the bottom, getting the optimal suction angle and position via experiment, which improves the efficiency of coal pneumatic feeding and discharging. Results:: A pneumatic feeding and discharging system and method are proposed for a coal storage silo with a high degree of integration and safety. Through similar experiments, it is concluded that the conveying efficiency is highest when the suction feeder is 30 mm high from the bottom, and the angle of the suction feeder is 45°. This provides theoretical support for the specific application of the device. Conclusion:: By analyzing patents and researching similar experiments, the proposed closed storage system for coal can improve coal conveying efficiency, reduce environmental pollution caused by coal particles during conveying, and decrease the possibility of spontaneous combustion and explosion of coal dust. The system is highly automated, easy to operate, and widely applicable.

Performance Analysis of Permanent Magnet Synchronous Generator for Small Scale Wind Energy Applications

This paper presents a study of the performances of a permanent magnet synchronous generator (PMSG) used in small scale wind energy applications. The d-q model is adopted for the performance analysis of the PMSG under variable operating conditions. In addition, in order to validate the results obtained with the theoretical model, an experimental test bench based on a small PMSG equipped with a data acquisition system has been developed. The study carried out on the experimental test bench made it possible to determine both the dynamic and the steady state performances of the PMSG under variable loads and rotational speeds.

Effect of temperature and velocity inlet conditions at the diffusers on the thermal and dynamic behavior of an impacting swirling multi-jet system

This study concerns the numerical simulation of a system of swirling turbulent jets impacting a flat plate, by two numerical models of the closure of the Navier Stokes equations (k-ω sst). The jet impact technique is widely applied in the field of heating, drying and cooling of industrial objects. The experimental test bench comprising a diffuser of diameter D, impacting the perpendicular plate, such that the impact distance H = 4D. The swirl is obtained by a swirl generator, made up of 12 fins arranged at 60° from the vertical, placed just at the outlet of the diffuser. The temperature of the swirling jets blowing on the plate is measured with a VELOCICALC PLUS portable thermo-anemometer device, in different stations. It is noted that this diffuser configuration having balanced inlet temperatures (T, T, T), gives a uniform distribution of temperature and velocity on the surface of the plate. This temperature distribution results from a 95% spread of homogenization of plate heat transfer. The (k-ω sst) model gave temperature and velocity profiles that coincide with those of the experimental results. By way of comparison, the (k-ω sst) model better predicts impacting jets, particularly in fluctuating zones. The latter remains a relatively better numerical simulation tool in terms of quality.

Experimental study on the influence of gas-blowing flow rate on the cold discharge characteristics of external ice-melting ice storage system

External ice-melting ice storage system has the advantage of fast cold discharge. However, the instability of outlet water temperature limits its practical application. In this paper, an experimental bench is built for testing cold discharge performance of the external ice-melting ice storage system combined with a gas-blowing device based on theoretical analysis. The influence of different gas-blowing flow rates on the vertical temperature distribution inside the ice storage tank, outlet water temperature, cold discharge rate, instantaneous cold discharge capacity, and total cold discharge capacity is analyzed and compared during the cold discharge process by experiments. The experimental results show that as the gas-blowing flow rate increases, the convective heat transfer between the water and ice in the water space of the ice storage tank is enhanced, the outlet water temperature decreases, and the cold discharge rate increases. Through comprehensive analysis, it is found that for a small external ice-melting ice storage system in this experiment, the outstanding comprehensive performance can be achieved with 1L/min gas-blowing flow rate, which. The average outlet water temperature during the latent heat phase is 1.9 °C lower and the cold discharge rate is 34.8 % higher than that without gas blowing.

Simulation and experiment on improving NOX conversion efficiency of ship selective catalytic reduction system

Selective catalytic reduction (SCR) technology is the main means of reducing NOX emissions. Urea injection structure parameters (i.e., the hole number in a nozzle, spray angle, the distance between the nozzle and the front section of the catalyst) and operating parameters (i.e., exhaust gas temperature, gas hourly space velocity, ammonia-to-nitrogen ratio (ANR)) of the SCR systems have a significant impact on denitrification efficiency (deNOX). A three-dimensional simulation model is developed to investigate the impact of diverse parameters on deNOX. The influence of temperature, ANR and space velocity on the deNOX of SCR system is studied by using the control variable method. The simulation model is modified according to the SCR catalyst gas distribution test results. A diesel bench experiment is conducted to test the deNOX of the SCR system of D2 cycle and two additional operating points to verify the accuracy of the numerical simulation model. Based on this model, the influence of key factors on the deNOX of SCR system is studied. In SCR system, the optimal urea injection angle is about 75°, the optimal number of nozzle holes is 4, the distance between the optimal urea injection point and the front section of the catalyst is 8 times of the pipe diameter, and the optimal operating temperature is 300 ∼ 420℃. The influence trend of ANR on deNOX at different temperatures is obtained. This provides a theoretical support for the realization of SCR system in the future.

Non-dominated sorting artificial rabbit multi-objective sizing optimization for a conceptual powertrain of a 6 × 4 battery electric tractor truck

In order to tackle the increasingly severe energy crisis, improving the efficiency of the powertrain system in battery electric vehicles has become an effective approach. Based on a 6 × 4 battery electric tractor truck (BETT), the paper focuses on enhancing the dynamic and economic performance of vehicles through advancements in configuration, control strategies, and parameter design. Firstly, a novel multi-motor torque coupling powertrain system based on the parallel-axle transmission is proposed and modeled. Then, an instantaneous minimum energy consumption control strategy for the economic performance simulation and an instantaneous maximum acceleration control strategy for the dynamic performance simulation are designed. Furthermore, a conventional heuristic single-objective optimization algorithm, artificial rabbit optimization (ARO), is improved into a multi-objectives version, non-dominated sorting artificial rabbit multi-objective optimization (NSARMO), by combining the fast non-dominated sorting (FNS) and modifying the calculation method of the energy factor. Finally, an optimization framework consisting of a control layer, model layer, and optimization layer is established and applied to the parameter optimization of the proposed powertrain system. Simulation results demonstrate that the optimization results of the proposed method are superior to those optimized by commonly used non-dominated sorting genetic algorithm-II (NSGA-II) and NSARMO without the modified energy factor, achieving a better balance between dynamic performance and economic performance. Moreover, the proposed method exhibits demonstrates 40.67% and 24.67% improvement in its ability to search for optimal Pareto solutions compared to NSARMO (-)(- means the calculation method of energy factor is not modified) and NSGA-II. At last, a hardware-in-the-loop (HIL) experiment bench is established, and the experiment results indicate that a scheme optimized by the proposed NSARMO exhibits only an approximate performance in energy consumption in the HIL environment compared to the simulation environment, which signifies the effectiveness of control strategy equipped with the optimization results optimized by the proposed method.

Coupled Computational and Laboratory Investigations of Interface Interactions between Binary Polymers, Hydroxypropyl Guar, and Potassium Formate for Crosslinked Hydraulic Fracturing Fluids

Summary Guar gum is an economically and environmentally important material. However, reduced rheological properties of hydroxypropyl guar (HPG) in saline conditions of potassium formate (PF) impeded its hydraulic fracturing (HF) applications. In this study, we coupled molecular dynamics simulation and bench experiments to design binary polymers that can be used to mitigate the reduced viscosity of the HPG-PF system and investigate the relevant physiochemical processes in the fluid. The modeling showed that binary polymer P(AM-AA) with acrylamide (AM) and acrylic acid (AA) monomers had the highest ability to bind water molecules in the HPG-PF solution among four representative binary polymers. Multiple analyses showed that adding P(AM-AA) decreased the number of formate ions around the HPG molecules, bonded with the HPG molecule through hydrogen bonds, and mitigated the coiling of the HPG molecular chain in PF solutions. Further experiments and characterization at the macro- and microscale showed that adding P(AM-AA) indeed improved the viscosity, microrheology, viscoelasticity, and thermal tolerance [>120°C (248°F)] of the HPG-PF solution (1.47 g/cm3) and its associated gel system. Our study indicates the potential application of HPG-PF-P(AM-AA) weighting crosslinked HF fluids (HFFs) for wells with stringent wellbore pressure constraints. It also highlights the significant role of binary polymers in enhancing rheological properties in gel-based crosslinked HFF and addressing complex fluid interface interactions through molecular dynamics simulations.

Structural and dynamic evaluation of a test bench for mechanical vibrations using finite elements

This numerical study was conducted to assess the experimental bench structure’s adequacy for measuring mechanical vibrations. The bench allows for three types of tests: dynamic imbalance of a single flywheel, dynamic imbalance of dual flywheels, and dynamic imbalance due to defective gears. A CAD (Computer-Aided Design) model of the vibration bench was developed in three distinct configurations. We then conducted structural (static) and dynamic (non-linear) analyses to assess the structural integrity of the bench, its components, and the expected vibration amplitudes during testing. Additionally, the structure’s natural frequencies were determined, and their compatibility with the expected excitation frequencies was confirmed. These assessments were executed using finite element models within the Solidworks Simulation™ framework. The findings indicate that, when designing such machinery, it is crucial to ensure that the vibration modes do not coincide with the excitation frequencies, as this can compromise the experimental results. Consequently, we have proposed and accessed two redesigned versions of the bench to ensure structural integrity and prevent resonance during experimental procedures. The redesigns aim to mitigate the risk of resonance by altering the bench’s structural parameters to shift the natural frequencies away from the range of excitation frequencies. This proactive approach is based on the idea that a big difference between the natural and excitation frequencies lowers the chance of resonance, which makes the results of the experiment more reliable. The enhanced designs were subjected to a series of rigorous simulations to validate their performance, ensuring that they meet the stringent requirements for educational and research applications.

Hybrid energy storage system for electric motorcycles: Technical and economic analysis

This paper presents the multiple energy storage system usability for electric motorcycle focused on hybrid topology. This study focuses on evaluating the cost-effectiveness of a hybrid energy storage system (HESS) for e-motorcycles over a 10-year period by considering the number of battery replacements instead of solely the initial system price. The motorcycle studied in this manuscript, is a recreational electric motorcycle utilized as an experimental test bench in EV-SCHS laboratory at the OJEN company. The 10-year equivalent price of the energy storage system includes both the initial purchase cost and the cost of battery replacements over the system's lifespan. A battery life model is essential for estimating the frequency of replacements over the 10-year period. Incorporating ultracapacitors (UC) in the HESS enhances power specifications, leading to improved acceleration and regenerative braking capabilities. This reduces battery current and extends battery life, resulting in fewer required replacements and lower overall system costs over the 10-year period. The study findings demonstrate that optimally-sized HESS configurations offer favorable power specifications, with the 10-year equivalent price of HESS being $3466 lower than that of conventional energy storage systems, despite the initial price of HESS being $833 higher.

Vibration response analysis of boneless wiper-windshield system based on multi-body dynamics model

The vibration and noise generated by the boneless wiper-windshield system during its actual operation bother the occupants. Exploring the dynamic characteristics of the boneless wiper-windshield system is a prerequisite for understanding vibration and noise. In this paper, the dynamic characteristics of the boneless wiper-windshield system are investigated, and a rigid-flexible coupled multi-body dynamic model matching the real boneless wiper-windshield system is constructed. The friction characteristic of the dynamic model is studied through the wiper test bench experiment. The nonlinear dynamic response of the dynamic model is calculated with the Adams and results of the frictional vibration are well reproduced in real motions. The parallel analysis of the simulation calculation results and the real vehicle test results confirms the validity of the model. The results show that the vibration generation mechanism at the moments before and after the reversal can be explained by the instability of the wiper blades due to the negative friction characteristic. There are differences in the magnitude of the reversal impact force and the moment of reversal at each position of the wiper blade. The effect of the speed-gears on the system vibration is analyzed through the simulation results. The analysis method and simulation results in this article can provide reference for the research on vibration and noise control of boneless wiper systems.

Status of the Deep Learning-Based Shattered Pellet Injection Shard Tracking at ASDEX Upgrade

Plasma disruptions pose an intolerable risk to large tokamaks, such as ITER. If a disruption can no longer be avoided, ITER’s last line of defense will be the Shattered Pellet Injection. An experimental test bench was created at ASDEX Upgrade to inform the design decisions for controlling the shattering of the pellets and develop the techniques for the generation of the fragment distributions necessary for optimal disruption mitigation. In an effort to analyze the videos resulting from the more than 1000 tests and determine the impact of different settings on the resulting shard cloud, an analysis pipeline, based on traditional computer vision (CV), was created. This pipeline enabled the analysis of 173 of the videos, but at the same time showed the limits of traditional CV when applied in applications with a highly heterogeneous dataset such as this. We created a machine learning-based (ML) alternative as a drop-in replacement to the original image processing code using a semantic segmentation model to exploit the innate adaptability and robustness of deep learning models. This model is capable of labeling the entire dataset quickly, accurately and reliably. This contribution details the implementation of the ML model and the current state and future plans of the project.

Electromagnetic Torque Components Analysis of Ultra-High-Speed Permanent-Magnet Synchronous Motor for Fuel Cell Air Compressor

The ultra-high-speed electric air compressor (UHSEAC) is affected by the electromagnetic torque components of the ultra-high-speed permanent magnet synchronous motor (UHSPMSM) during wide-range speed regulation, resulting in intense speed fluctuation. Electromagnetic torque components are generated by the effects of permanent magnet field harmonics, stator slotting, and current harmonics. It is very important to conduct simulation comparisons and theoretical descriptions of different sources of pulsation factors. In this paper, firstly, the electromagnetic torque model of UHSPMSM with a rated speed of 80,000 rpm is constructed and verified by an experimental bench. Secondly, the electromagnetic torque components of UHSPMSM are extracted on the basis of the electromagnetic torque model. Finally, the electromagnetic torque components’ characteristic law is investigated under different ultra-high-speed operating conditions. The results show that under ultra-high-speed operation, the frequency and amplitude of electromagnetic torque components become larger with increasing speed. And the amplitude of electromagnetic torque components becomes larger with increasing torque. This paper constructs the observation object of the high-frequency state observer and does the preliminaries for the design of the UHSEAC controller.