Experimental Bench Research Articles

Experimental study of phase change heat dissipation system based on hydrogen fuel cell

In order to improve the internal heat dissipation efficiency of the proton exchange membrane fuel cell, this paper designs and builds a set of fuel cell heat dissipation system experimental bench with a heat dissipation capacity of 15 kW based on the separated heat pipe technology, and investigates the heat dissipation characteristics of the HFE-7100 and ethylene glycol aqueous cooling medium under different condenser processes and different ambient temperatures. The results show that at an ambient temperature of 35 °C, under the same condenser flow arrangement, the two-phase heat dissipation efficiency of HFE-7100 is higher than that of glycol aqueous solution liquid cooling, and its heat dissipation and EER (Energy Efficiency Ratio) are increased by 81.2 %∼98.8 % and 68.2 %∼86.6 %, respectively. The best effect is achieved when the condenser is 3-process, with two-phase heat dissipation of 14.1 kW and EER of 20.5 kW/kW, which are 82.8 % and 68.9 % higher than liquid cooling, respectively. As the ambient temperature rises, the two-phase heat dissipation effect is further improved, and at 50 °C ambient temperature, the heat dissipation is 10.44 kW, which is 145 % higher than that of liquid cooling, and the EER is 15 kW/kW, which is 132 % higher.

A Single-Output-Filter Double Dual Ćuk Converter

This study introduces an innovative version of a recently studied converter. A Double Dual Ćuk Converter was recently studied with advantages like the possibility of designing it for achieving a low-input current ripple. The proposed converter, called the Improved Double Dual Ćuk Converter, maintains the advantages of the former one, and it is characterized by requiring one less capacitor and inductor than its predecessor. This allows addressing the challenge of optimizing the topology to reduce component count without compromising the operation; this work proposes an efficient design methodology based on theoretical analysis and experimental validation. Results demonstrate that the improved topology not only retains the advantages of the previous version, including high efficiency and robustness, but also enhances power density by reducing the number of components. These advancements open new possibilities for applications requiring compact and efficient power converters, such as renewable energy systems, electric vehicles, and portable power supply systems. This work underscores the importance of continuous innovation in power converter design and lays the groundwork for future research aimed at optimizing converter topologies. A detailed discussion of the operating principles and modeling of the converter is provided. Furthermore, simulation outcomes highlighting differences in steady-state duration, output voltage, input current ripple, and operational efficiency are shared. The results from an experimental test bench are also presented to corroborate the efficacy of the improved converter.

Enhancing flocculation kinetics assessment: Integrating aggregate size distribution into experimental and modelling frameworks

Flocculation is crucial in drinking water treatment, yet conventional techniques like jar tests may lack precision in capturing particle heterogeneity. To overcome this, a non-intrusive image-based system was employed to directly assess flocculation using aggregate size distribution (ASD). Integrating ASD into a kinetic model with a single parameter (β) allowed for tracking ASD during flocculation. Bench and pilot-plant scale experiments validated our approach. Sensitivity analysis confirmed β's responsiveness to ASD variations (r > 0.92), with modelling indicating errors averaging around 5%, underscoring its efficacy in assessing flocculation efficiency. Linking ASD coefficients from bench to pilot-scale models facilitates predicting flocculation performance.

Experimental Characterization of Commercial Scroll Expander for Micro-Scale Solar ORC Application: Part 1

In order to reduce greenhouse gas emissions and achieve global decarbonisation, it is essential to find sustainable and renewable alternatives for electricity production. In this context, the development of distributed generation systems, with the use of thermodynamic and photovoltaic solar energy, wind energy and smart grids, is fundamental. ORC power plants are the most appropriate systems for low-grade thermal energy recovery and power conversion, combining solar energy with electricity production. The application of a micro-scale ORC plant, coupled with Parabolic Trough Collectors as a thermal source, can satisfy domestic user demand in terms of electrical and thermal power. In order to develop a micro-scale ORC plant, a commercial hermetic scroll compressor was tested as an expander with HFC-245fa working fluid. The tests required the construction of an experimental bench with monitoring and control sensors. The aim of this study is the description of the scroll performances to evaluate the application and develop optimization strategies. The maximum isentropic effectiveness is reached for an expansion ratio close to the volumetric expansion ratio of the scroll, and machine isentropic effectiveness presents small variations in a wide range of working conditions. The filling factor is always higher than one, due to leakage in the mechanical seals of the scroll or other inefficiencies. This study demonstrates that using a commercial scroll compressor as an expander within an ORC system represents a valid option for such applications, but it is necessary to improve the mechanical seals of the machine and utilize a dedicated control strategy to obtain the maximum isentropic effectiveness.

Research on Damping Hole Optimization of Hydro-Pneumatic Suspension for Mining Trucks under Variable Load Conditions

The hydro-pneumatic suspension, known for enhancing vehicle ride comfort and stability, finds widespread use in engineering vehicles. Presently, the majority of mining trucks employ hydro-pneumatic suspension with a fixed damping hole, underscoring the critical importance of selecting appropriate damping hole parameters. Initially, an equilibrium mathematical model of the ¼ hydro-pneumatic suspension is established, and the influencing factors of the damping characteristics are analyzed. Subsequently, the simulation model and experimental bench for the hydro-pneumatic suspension are constructed. Sinusoidal signals with different frequencies and amplitudes serve as the excitation signals to analyze the variation trend of the force on the rod with displacement changes. The simulation and experimental results demonstrate a high degree of consistency, validating the rationality and validity of the simulation model. Building upon this foundation, various damping apertures are then selected to study the damping characteristics of the hydro-pneumatic suspension. The research indicates that as the damping aperture increases, the setting time of the hydro-pneumatic suspension system after excitation extends, accompanied by a decrease in the acceleration overshoot. As a result, a comprehensive evaluation index is developed, considering various factors, such as different weight setting times and peak longitudinal accelerations to assess the ride comfort of the suspension. This approach is then employed to determine the optimal damping aperture under both full-load and no-load conditions. The findings of this research offer valuable insights for the development of adaptive variable damping hydraulic suspensions, especially under variable load conditions.

水稻穴播器取种装置设计与试验

The core equipment of rice dry direct-seeding with film mulching devices shows poor adaptability to rice varieties, struggling to accommodate diverse seeding quantity for both hybrid and conventional rice varieties. A seed-filling component with unilateral and bilateral seed-filling function was designed to solve this challenge. Through theoretical analysis the key structural parameters of the seed-filling component were determined. Then Discrete Element Method (DEM) simulations were conducted to analyze the seeding performance, leading to the identification of optimal parameters for orifice width and orifice deflection angle of the seed-filling component, which are 7.7 to 8.5 mm and 1.71 to 2.41 degrees, respectively. Bench experiments using the central composite design indicates that the optimal parameters for the seed-filling component's orifice width and orifice deflection angle are 8.1 mm and 1.99 degrees, respectively. In the optimal combination of orifice parameters, for unilateral seed-filling in hybrid rice, the miss-seeding rate is 4%, the qualified rate is 84.8%, and the reseeding rate is 11.2%. For bilateral seed-filling in conventional rice, the miss-seeding rate is 4.2%, the qualified rate is 85.2%, and the reseeding rate is 10.6%. The result of field hole-seeding with film mulching is consistent with the result of indoor bench experiments, demonstrating that the seed-filling component of the hole seeder can meet the seeding requirements for rice precision direct-seeding with film mulching. This paper provides theoretical reference for the design and optimization of the seed-filling component for rice hole-seeding equipment.

Analysis of interval type-2 fuzzy controller based interleaved sepic PFC converter for PQ enhancement in power solutions

The Power solutions have become indispensable for all the devices in recent years with an appropriate power conversion circuitries and control methods to ensure good dynamic response, improved stability, reliability and efficiency. The main intent of this article is to impart the designing of interval type-2 fuzzy logic controller (IT2FLC) based interleaved Sepic power factor correction (PFC) converter. This work also involves the careful design of the robust controller with enhanced precision and good power quality (PQ) performance at the AC mains. In addition, the development of IT2FLC based power solution improves the overall power conversion with stabilized output in the perspective of its quick rise time, less overshoot and fast settling time in comparison to other traditional controllers. Further, the uncertainties and issues associated with the conventional proportional integral (PI) and fuzzy logic controllers (FLCs) are handled effectively by the proposed IT2FLC controller. Moreover, this preferred converter is modeled with an internal parasitics and its performances are evaluated and compared with other conventional Zeigler Nicholas (ZN) tuned PI controller and FLC by dint of MATLAB/Simulink platform. Finally, the experimental test bench set up of 250 W, 48 V power circuitry is devised and the test outcomes confirm the excellent transient behavior and PQ performances of the modeled power solution.

EXPERIMENTAL STUDY OF LOAD EFFECT ON DEFORMED STATE OF ADJACENT PIPELINE SECTIONS WHEN USING A SUPPORT-CENTERING DEVICE

The relevance of the study is due to the testing of the results of the numerical calculation of the stress-strain state of the support-centering device and pipeline in ANSYS software through an experimental study. The purpose of the work is to experimentally study the effect of the support-centering device on the pipeline when centering the boundary sections when cutting out a defective coil during emergency repairs. The object of the study is an experimental bench of a pipeline with diameter Dн = 40 mm, chosen as a prototype of a pipeline with diameter Dн = 1020 mm. Research methods: mathematical modeling, experimental research, processing of experimental data.The following results were obtained:- the maximum deformation of the end of the pipeline in a computer model of a full-scale pipeline with an applied load of 10 kN is 62.9 mm, the maximum stress is 87.2 MPa;- factors identified: load F = 0–50 N, length of the free end of the pipeline l = 0.5–1.5 m, depth of the pipeline h = 50–80 mm) and experimental response - deformation u;- during the processing of experimental values of deformations, it was revealed that the depth of the pipeline does not affect the results of measuring the displacement of the pipeline axis from applied transverse forces, therefore, it was decided to carry out measurements at a constant depth of 0.08 m;- based on the results of the experiment, graphs of theoretical and experimental dependences of the movement of the pipeline axis on the longitudinal load were constructed: the difference between the two schemes for securing the pipeline is 41 %, in the calculations it is necessary to take into account the part of the pipeline located in the ground;- the relative error of the experimental results, taking into account theoretical errors, is no more than 10 %.

Study on the Flame Transition Characteristics of a Gas Turbine Combustor

Gas turbines are widely used as important equipment for electricity generation on islands and offshore platforms. During the operation of a gas turbine, the flame shape in the combustion chamber undergoes variations in response to changes in parameters such as gas turbine load, fuel distribution, and burner structure. These alterations in flame shape exert influence on combustion instability, emissions, and load characteristics. This study explores the variations in flame transition, emissions, and operating parameters among three distinct center stage structures: namely, the non-premix center stage (NPCS), premix center stage (PCS), and enhanced premix center stage (PCSE). The investigation is conducted using a heavy-duty gas turbine hybrid burner on a full temperature, full pressure, and full-size single burner experimental bench. Simultaneously, a multi-parameter numerical simulation regarding the influence of the central fuel split on flame shape analysis was conducted using the PCS burner under the design point for a more in-depth understanding of the mechanisms and for influencing factors associated with flame transition. The findings indicate that variations in flame transition loads among different central stage structures: for the NPCS burner, the transition occurs between 45% and 50% load; for the PCS burners, it takes place between 60% and 65% load; for the PCSE burners, it shifts between 55% and 60% load. Additionally, a reduction in NOx emissions is observed during the flame transition process. Furthermore, it was found that decreasing the central stage fuel results in a decline in flame angle for the same burner structure. As the central stage fuel diminishes to a specific value, the flame shape undergoes a sudden change. Further reduction in central stage fuel does not significantly affect the flame shape and temperature distribution.

Effect of the Main Operating Variables on Efficiency of Treating Industrial Flue Gases Using Potash and Yellow Phosphorus

Fossil energy is considered as an important source of energy used in different types of industries. However it emits a great amount of flue gases. Some components of flue gases such as SOx and NOx can cause negative environmental impacts. Acid rains, increasing greenhouse effects and causing humans health problem (for Respiratory system) are some of them. A bench scale experiments using: 2900 ppm SOx, 550 ppmNOx , 1L deionize water, 0.5 g P4, and 10 g MOP were conducted in order to investigate the effects of operating conditions in removing process. These conditions are: emulsion temperature, yellow phosphorus weight, and the emulsion stirring intensity. Optimum conditions for removing process are (55oc, 1743 rpm, using 0.5 g P4). It was also observed that emulsion’s pH and oxygen concentration are declined with reaction time, but they have a positive correlations with removing efficiency, whereas efficiency increasing when rising emulsions temperature and stirring intensity. The obtained results identified the optimum conditions to get the highest efficiency for removing SOx and NOx from flue gases to eliminate their environmental impact

An improved adaptive position tracking strategy for automatic shift actuator with uncertain parameters

Realizing precise and fast position control of the gear is a challenging issue because of its nonlinearity, parameter uncertainty and external disturbance. Therefore, this paper researches the clutch position control considering the influence because of the factor on the system performance. By virtue of the traditional adaptive control method, an improved strategy based on finite time theory is proposed to further improve the convergence rate as well as the position tracking precision. First, a model of electromechanical clutch actuator system is established by theoretical analysis. Then, an enhanced adaptive controller is designed using finite time idea by introducing power function in the virtual control. And parameter update rate is adopted in the control action. Next, the stability of the control system is proved theoretically. Finally, Matlab simulations and experimental bench test are carried out to exhibit the effectiveness of the presented method. The results show that the satisfactory performance has been achieved with accurate position tracking and fast convergence speed.

Characterization of rotary valve control vibration system for vibration stress relief applications

To enhance the vibration system characteristic distortion and pressure loss, we propose a novel rotary valve control vibration system. The paper presents the designed structural composition and generation mechanism of the rotary valve control vibration system. It also derives the mathematical model for the rotary valve distribution process and the overall system. The flow field inside the rotary valve is dynamically simulated using the multiple reference frame model, allowing for the determination of the change rule of the rotary valve’s output characteristics. An AMESim model was developed to analyze the vibration characteristics of the rotary valve control system. The effects of parameters such as inlet pressure, motor speed, and oil supply pump displacement were investigated. A rotary valve control vibration system experimental bench was constructed to experimentally verify the output characteristics of the rotary valve and the vibration characteristics of the system. The results indicate that the characteristic curve of the designed vibration system closely resembles a sinusoidal wave. Additionally, the rotary valve exhibits low pressure loss, making it more suitable for vibration stress relief applications. By appropriately increasing the inlet pressure and decreasing the motor speed, the vibration characteristics of the system can be improved.

Effect of width on the fire spreading characteristics of PE metal sandwich panels under the action of double fire sources

The exterior walls of high-rise buildings typically contain substantial thermal insulation materials. Once ignited, these materials can readily induce major fire accidents. In this study, through the constructed reduced-size experimental bench to evaluate the effect of window overflow fire and upper chamber fire on the fire spreading properties of PE metal sandwich panels with different widths. The result shows that the average flame height and flame oscillation intensity increased with an increase in fire source power and sandwich panel width. Temperature curves exhibited a consistent trend under different working conditions. Dimensionless analysis of the sandwich layer temperature indicated that under specific fire source power conditions, the 60 cm sandwich panel reached the highest peak temperature and posed the greatest fire hazard. Based on the width and length of the preheating zone, a model for the rate of flame spreading was created. At a constant sample width, the accelerated spread of the upper part of the plate by the action of fire source B was more obvious. These conclusions are instructive for the study of building facade fire.

Design and Experiment of Plate Taking Control System of Edible Sunflower (Edulis helianthus catino L.) Harvester

This study aims at the problems of high labor intensity, high cost and high loss rate of mechanical picking of seeds, low mechanization level and difficulty to guarantee the quality of picking plates in the process of picking edible sunflower. Based on the principle of manual plate taking, a plate taking control system for a sunflower harvesting table was designed. The principle of taking the plate of the edible sunflower harvesting table was analyzed. According to the actual operation requirements, the overall scheme of the sunflower plate control system is determined, and the control strategy of imitating artificial low-loss harvesting is designed. To reduce the grain loss in the process of taking the plate and improve the control accuracy of the system on the movement speed and displacement of the key components in the process of taking the plate, a trapezoidal acceleration and deceleration control algorithm is designed as the control algorithm of taking the plate. The working performance of the plate control system was verified with the absolute error, relative error and total loss rate of the harvest as objectives. Bench and field verification experiments were both carried out. The bench experiment showed that the speed error of the plate parts was not more than 0.028 m/s. In the bench experiments of the device, the maximum positioning error was 1.25 mm, the average relative error was only 0.94% and the grain loss rate was not more than 2.26%. Its result showed that the system algorithm was reliable, the positioning accuracy was high and the plate taking operation can be completed well. The field verification experiment showed that the forward speed of the unit was in the range of 0.4~0.8 m/s, and the total loss rate of harvest was less than 5%. When the forward speed is 0.6 m/s, the minimum harvest loss rate is 2.32%, which indicated the control system meets the requirements of sunflower harvesting operation.

Evaluation of the strength performance of the steering system of hybrid off-road vehicles

In response to the strength performance requirements of the new energy Off road Vehicle steering system, this article analyzes and studies the strength performance and failure modes of the new energy Off road Vehicle steering rod based on a certain new energy Off road Vehicle model through simulation, bench experiments, and vehicle strength testing teams. Based on various vehicle misuse conditions, the force law of the steering rod under different vehicle driving conditions was analyzed, and a load spectrum for the steering rod strength bench test was developed to meet the actual vehicle usage conditions. The results indicate that the steering rod strength failure is mainly manifested as bending failure of the compression rod under alternating tension and compression conditions. Finally, based on the stability principle of the compression rod, the requirements for the strength performance index of the steering rod are proposed. The research results can provide certain technical support for the strength assessment of the vehicle steering rod.

Parameter identifications of synchronous vibration of rotating blades with large amplitude based on blade tip timing

Blade Tip Timing (BTT) is a promising method to measure the vibration of rotating blades by installing probes on the casing. The Zablotsky-Korostelev Single Parameter Technique (SPT) is widely used to identify the vibrational characteristics of blade synchronous responses. This method assumes that the influence of blade’s own vibration on arrival time can be neglected. However, it is reported that vibrations of rotating blades with large amplitudes will cause errors in identifying maximum vibration amplitude because of the above-mentioned assumption. In this paper, we derived a mathematical model of single degree of freedom (SDOF) blade model discarding the assumption of small amplitude related to BTT actual measurement. Compared to traditional SPT, our model takes the influence of blade’s own vibration into consideration. Then, we improved SPT and derived a precise measurement formula. Arrival time of blade to the sensor was revised. Based on this, we conducted a parametrical study on the effects of changes in various factors including excitation force, damping ratio, engine order, and the installation position of the sensor by numerical simulations. Displacements between considering blade’s own vibration and not were compared. Errors in fitted parameters were also analyzed. The numerical simulation results show that large engine order will magnify the error in fitted parameters if traditional SPT was used. Damping ratio and maximum vibration amplitude have relatively large errors in fitting parameters. Furthermore, we designed an experimental bench to verify the mathematical model and the revised measurement formula.

Wave Energy Converter Power Take-Off Modeling and Validation From Experimental Bench Tests

Wave Energy Converter Power Take-Off Modeling and Validation From Experimental Bench Tests

双电机驱动电动拖拉机能量管理策略的研究

At present, electric tractors experience significant battery energy loss during operation, resulting in a short continuous running time. Therefore, in order to reduce the power consumption of the tractor drive system, minimize battery energy loss, and extend the operating time under various conditions, this paper presents a method for driving an electric tractor based on dual-motor coupling. Based on the characteristics of the transmission structure, an online torque distribution strategy for dual-motor coupling-driven electric tractors using a fuzzy control approach is proposed. First, an enhanced genetic algorithm is utilized to optimize the fuzzy rule table. Simultaneously, it is compared with the offline optimization strategy of dynamic programming. Subsequently, a method that integrates test data models and theoretical models is employed to establish an efficiency model of key components of the electric tractor drive system and a longitudinal dynamics model of the entire machine. The performance of the entire vehicle was simulated and analyzed under plowing conditions. Finally, on the experimental bench, conduct steady-state load tests and dynamic performance tests on the dual-motor coupled drive system. The results show that the State of Charge (SOC) change trends of the fuzzy control strategy based on the improved genetic algorithm and the dynamic programming strategy are similar. The SOC change values are close, which enhances the adaptability of the electric tractor in various operating conditions. Compared with the fuzzy control strategy, the improved strategy reduced average power consumption by 8.8%, demonstrating that the fuzzy control energy management strategy based on the enhanced genetic algorithm is both economical and superior. The bench experiment demonstrated that the dual-motor drive system can adapt to load changes to achieve power distribution between the two motors, meeting the required workload while reducing power consumption.

交错苗带式大豆精量免耕播种机设计与试验

According to the requirements of soybean stripping planting in the Huang-Huai-Hai region, a new planting mode was proposed, and a no-tillage staggered seedling belt soybean precision planter was designed. A seed-metering device with staggered distribution of sockets was designed. The optimal parameter combination was obtained through simulation analysis, and its structural rationality was verified through bench experiments. It achieved staggered seedling belt seeding; a retractable top rod seeding device was designed to improve seeding efficiency; the arrangement of the rotary cutter for the seedling belt cleaning and preparation device was designed to reduce work energy consumption. The field experiment results showed that when the forward speed was 8 km/h, the reliability and trafficability of the no-tillage staggered seedling belt soybean precision planter were qualified. The qualified rate of sowing depth was 92.6%, the qualified rate of grain spacing was 94.4%, the leak sowing rate was 1.8%, the repeat sowing rate was 38%, the seed exposure rate was 0.74%, and the operation efficiency was 1.92hm2/h.

Dynamic performance prediction and experimental analysis of wet clutch actuator considering thermal flow characteristics

The hydraulic actuator system (HAS) for wet clutches in heavy-duty vehicle transmissions is required to have a fast response and high precision in the pressure regulation procedure. Conventional pressure control valves for HAS are almost slide spool structures, which perform a large flow force at a high flow rate. An open-center spool structure is designed and developed in this paper, which is a combination of a traditional slide spool and a valve sleeve. It has an orifice-groove combination throttling orifice, which can take into account the large through-flow capacity and small flow force. Firstly, to deeply understand the mechanism of pressure variation in the clutch chamber, a high-fidelity dynamic characteristic mathematical model of HAS considering the oil temperature is proposed. Secondly, the functional relationship between the oil temperature on the medium physical property parameters and the orifice thermal flow parameters in the model is deduced in detail. An experimental bench to measure the pressure valve dynamic performance and actuator pressure regulation characteristics in a wide temperature domain is then designed and implemented to validate the accuracy of the simulation model. Finally, the mechanisms of oil temperature and system pressure on pressure impact and pressure response are quantitatively analyzed in association with a supervised learning algorithm. The feasible domains of the two adjustable variables are also explored. This study provides a new perspective on dynamic control and energy saving of HAS pressure valves and a new method for the prediction of HAS performance under complicated operating conditions.