Middle Speed Research Articles

STUDY ON TRIBOLOGICAL CHARACTERISTICS OF HOISTING EQUIPMENT BRAKE SYSTEM

In industrial production, there are strict requirements for the braking effect of heavy transport equipment such as elevator and belt conveyor. The working capacity and reliability of the brake are the basis for ensuring efficient production. Based on the friction and wear test, taking the average friction coefficient and stable wear rate as the key parameters to measure the reliability and stability of the brake, the friction and wear characteristics of the hydraulic disc brake of the hoist under different working conditions are analyzed and studied. The results shows that the average friction coefficient and stable wear rate of the brake fluctuate less with the change of brake pressure in the middle speed range. At this time, the adhesive and matrix fiber in the friction pad have not been decomposed and modified, and the strength and shape of the surface micro convex structure are relatively moderate, so the braking reliability is in good condition.

The flow deteriorations in course of the partial load operation of the middle specific speed Francis turbine

Abstract The article presents the results of experimental and numerical tests of a water turbine. As the object of the research the middle size Francis turbine, characterized by a middle value of specific speed, was taken into consideration. The primary aim of the realized project was to explain the occurrence of a high vibration level in a partial load operation. It was realized by the application of the superposition of experimental methods and a numerical simulation. The numerical results were verified on the basis of comparison with experimental results obtained for the real turbine. The numerical models were built with great accuracy to the reality and the flow was recognized, which allows to explain the reasons for random occurrence of high vibration in a draft tube and indicate a possibility of improvement of the analyzed object. The results of the numerical research such as distributions of velocity, pressure and vapor volume fraction in the passages were taken into consideration. The flow inside the Francis turbine and an outflow chamber were conscientiously analyzed. Pressure and velocity distribution as well as water surface structure were presented in the paper. Furthermore, the results numerical investigations helped to describe a cavitation rope vortex creation in the draft tube and the development of the air vortexes in the outlet chamber. Finally, the superposition of those phenomena was responsible for the deterioration of the turbine operation.

Optimization of spiral continuous flow-through pulse light sterilization for Escherichia coli in red grape juice by response surface methodology

The effect of a spiral continuous flow-through pulsed light (PL) system on the inactivation of Escherichia coli in red grape juice was evaluated. The grape juice was treated with different numbers of pulses, intensities of PL and liquid flow rates. Reduction of E. coli was determined by plate counting method. Response surface methodology was used to analyze the correlation among the factors. The results showed the inactivation effect increased with intensities and pulse numbers. Middle speed of flow rate could obtain the highest inactivation effect. Reductions of 2.1, 2.6 and 3.7 log were achieved in treatment of 100 pulses, 30 mL/min flow rate, intensities of 0.13, 0.40 and 0.66 J/cm2/pulse, respectively. Reductions of 1.0, 3.1 and 1.7 log were achieved in treatment of 100 pulses, 0.66 J/cm2/pulse, flow rates of 0, 30 and 60 mL/min, respectively. As verifying tests from the optimization exercise, with the spiral continuous flow-through PL treatment, the number of E. coli reduced by 4.89 log CFU/mL at the optimal levels of 80 pulses, intensity of 0.66 J/cm2/pulse and flow rate of 40 mL/min. These results suggest that the spiral continuous flow PL could improve the inactivation of E. coli in red grape juice.

Simulation analysis of efficiency and stability for vehicle’s ABS control on combined steering and braking maneuvers

Eight degrees of freedom vehicle model was established. Using the method of fuzzy control, the ABS control algorithm was designed based on slip ratio. Simulation analysis was done at speed of 15m/s, 20m/s, 25m/s under turning braking. The results show that the vehicle braking performance and vehicle stability at middle or low speed was improved by using the ABS controller, but qualitative analysis shows that phenomenon of vehicle instability was appeared at high-speed conditions. The turning braking stability under ABS controller was judged quantificationally by the stability judging formula. The results show that the requirements of stability control could not meet with only Anti-lock Braking System.

Design of Steering Controller of Automated Driving Bus at Middle Speed Range

Design of Steering Controller of Automated Driving Bus at Middle Speed Range

Adaptive Real-Time Energy Management Strategy for Plug-In Hybrid Electric Vehicle Based on Simplified-ECMS and a Novel Driving Pattern Recognition Method

This paper proposes an adaptive real-time energy management strategy for a parallel plug-in hybrid electric vehicle (PHEV). Three efforts have been made. First, a novel driving pattern recognition method based on statistical analysis has been proposed. This method classified driving cycles into three driving patterns: low speed cycle, middle speed cycle, and high speed cycle, and then carried statistical analysis on these three driving patterns to obtain rules; the types of real-time driving cycles can be identified according to these rules. Second, particle swarm optimization (PSO) algorithm is applied to optimize equivalent factor (EF) and then the EF MAPs, indexed vertically by battery’s State of Charge (SOC) and horizontally by driving distance, under the above three driving cycles, are obtained. Finally, an adaptive real-time energy management strategy based on Simplified-ECMS and the novel driving pattern recognition method has been proposed. Simulation on a test driving cycle is performed. The simulation results show that the adaptive energy management strategy can decrease fuel consumption of PHEV by 17.63% under the testing driving cycle, compared to CD-CS-based strategy. The calculation time of the proposed adaptive strategy is obviously shorter than the time of ECMS-based strategy and close to the time of CD-CS-based strategy, which is a real-time control strategy.

METROLOGICAL CHARACTERISTICS OF THE HIGH PRESSURE REGISTRATION IN INJECTION FUEL SYSTEMS OF DIESEL ENGINES WITH APPLICATION OF THE COMBINED TRANSDUCER

The technique of the harmonious analysis of metrological characteristics for record of non-stationary processes is presented. Furies method is used in the apply to tasks of graphic and tabulated form data processing. Furies coefficients were calculated by means of the approached integrations method with use of rectangular formulas. The algorithm and the program, adopted for measurement of fuel injection parameters of diesel engines, is developed. Program realization has the wide spectrum of options providing the optimum interface and the form of representation of results of the analysis. It was carried out research of amplitude -frequency parameters of measuring system on the basis of the combined converter for fuel pressure. As the converter was used the constructive element of the marine middle speed diesel fuel injection system. Pressure of fuel in FPHP was measured with two transducers: base of traditional design and experimental. Engineless tests in boards of the of rotation frequencies, overlapping operational limits of the engine, are lead. Experimental data are processed in the environment of the developed package. Peak-frequency characteristics of measuring system in comparison of the combined and base converter of pressure of fuel are certain. Discrete Furies transformation was made with show of result in the form of the diagram of amplitudes the spectral components on the screen and for the visual control return Furies transformation also with a show of the diagram of function to the screen. It is established, that the system with the combined converter has parameters close to a base variant on all modes except the fractional injection.

PO-200 Research on the running ability of young male soccer player

Objective Running is the main form of sports in a football match, and running distance is an important factor affecting the outcome. Monitoring the running ability of the athletes in the competition can fully understand the load and physical fitness of the athletes, and provide data reference for the coaches to formulate scientific and systematic training programs.
 Methods The first 7 warm-up matches of the Guangdong U18 men's football team in 2017 were selected as the research object, and the MT-sports football training monitoring system was used to collect the running data of 10 first players. According to the position on the field, they are divided into the outside fullback, the center back, the center defence midfield, the center attack midfield, the outside attackers and striker. For the purpose of comparison, this study used the running grade standard formulated by Danish scholar Bosber.
 Results (1)overall movement of athletes
 The average running distance of the 7 warm-up matches is 7945m, and the jogging distance is 4368m, accounting for 55% of the total running distance; the middle speed running distance is 2574m, accounting for 32.4% of the total running distance; the running distance above the high speed running is 1006m, accounting for 12.6% of the total running distance. The average running speed of the 7 games is 1.30m/s, and the average maximum speed is 7.80m/s.
 (2)The running distance of athletes at different speeds on different positions
 The average total running distance of the center attack midfield is 8759m, and the high-speed running distance is 1226m, which is the highest, and the high-speed running distance accounts for 13.9% of the total running distance. The high speed running distance between the outside fullback and the outside attackers is basically equal, the field is 1215m and 1158m respectively, but the high speed running distance has the highest total distance, reaching 14.7% and 15.3% respectively. The average running distance of the striker is 8134m, and the distance from the high speed running is 1027m, which is only higher than that of the center defence midfield and the center back. The running distance and the high speed distance of the center backs are below the average.
 Conclusions (1)There is a certain gap between athletes and elite athletes in running ability, but in high-intensity running ability is more prominent.
 (2)Athletes have more walking distance, which suggests that players should be encouraged to move actively in the future training process.
 (3) The center attack midfield has prominent running ability and strong speed running ability in the competition.
 (4) The running situation of the center defence midfield is similar to that of the center attack midfield, but the high-speed running distance of the center defence midfield is only slightly higher than that of the center back, which also reflects the running form of the center defence midfield players.
 (5) The striker's running ability is general in the competition. The high-intensity running distance is lower than that between the center attack midfield and the outside attackers, even the the Outside fullback, which may lead to tactical failure.

L28/32H 중속 디젤엔진용 연료분사펌프의 성능 비교

A fuel injection pump for L28/32H middle speed engine was manufactured by the domestic technology, then measured its major parts in order to analyze precisely its performance. The experimental apparatus had been made especially to evaluate the performance of fuel injection pumps manufactured by a domestic “P” corporation and a foreign “N” corporation and then the injection pressure and the injection quantity of those pumps had been investigated and compared with each other. As a result, principal dimensions, injection times, pressure delivery speeds, max. injection pressures and injection quantities of fuel which could affect the engine performances were very similar to each other. While residual pressures in fuel injection pump of P corporation was higher than that in N corporation due to the force of the delivery valve spring.

波形解析結果による船型改良の試み : 第1報 Mathieu関数展開法 (中速船)

波形解析結果による船型改良の試み : 第1報 Mathieu関数展開法 (中速船)

Analysis of laser damage and gettering effect induced by laser boron doping

In the present work, laser damage on laser boron doped silicon wafers is studied. Direct evidences of two different laser damages are observed with SEM/STEM: pores appearing in the surface and dislocations in the bulk. Statistical pore size distributions illustrate a downtrend of pore size with laser scan speed increasing. The crystallinity of wafer surface before and after laser doping is also characterized and analyzed by using Raman spectroscopy together with the volume fraction of crystalline Xc. The broadened and fitted Raman bands as well as Xc values present consistent evidence of amorphous silicon introduced in the wafer surface after laser doping. Gettering effect induced by laser doping is studied by taking iron concentration as standard. The highest gettering efficiency (~ 99.5%) is achieved at the middle laser scan speed (4 m/s), which most likely results from the joint effect of segregation coefficient and segregation time. Finally, the influence of laser doping on minority carrier lifetime is discussed with respect to a comprehensive consequence affected by laser damage, boron concentration and iron concentration.

The optimum design of falling-film evaporator and numerical simulation of distributor

The distribution of the refrigerant has a significant influence on the performance of the falling-film evaporator. The distributor is the key component in the falling-film evaporator, which determines the uniformity of the distribution of the refrigerant in the falling film evaporator. In this paper, the mathematical model of the refrigerant flow in the curly top surface structure of distributor was established and the model was studied using numerical simulations. The uniformity distribution of refrigerant in the distributor was analyzed. The result shows that the top surface of the distributors can improve the high speed refrigerant distribution near the inlet of the distributors, the header configuration with perforated baffle plate can avoid the middle speed getting larger, side speed is too small, the flow field is not uniform, the three rows of holes uniform discrete coefficients in the uniform plate are 0.11、0.09、0.15, respectively.

Numerical prediction and analysis of electromagnetic vibration and noise of claw pole alternator

With the improvement of internal combustion engine noise, the noise of claw pole alternator which is universally used on modern automobiles is becoming more distinct. Extensive experimental results show that the noise of claw pole alternator is annoying at low to middle speed and mainly originates from the electromagnetic noise. In this paper, a complete methodology for electromagnetic vibration and noise prediction of claw pole alternator is presented. It is a three-step multiphysics simulation. The first step is to calculate the magnetic force exerted on the inner surface of the stator using 3D FEM. The second step is the structural analysis, which is to investigate the natural resonant frequencies and modal shapes of the alternator system taking into account the real mechanical boundary conditions. The third is the electromagnetic vibration and noise calculation by using modal superposition method and boundary-element method, respectively. Simulation results agree well with those measured by experiments. Furthermore, the mechanisms of electromagnetic vibration and noise are analyzed by using the electromagnetic theory. The method can be used in the initial design stage of claw pole alternator and is also suitable for other types of motor.

Estimación del potencial de los trenes de media y alta velocidad en México con base en la demanda de pasajeros aéreos

It has been detected that in air short-haul up to 500 kilometers distances, the middle and high-speed train services have advantages over the air service. The objective of this research was to estimate the potential of these train services in Mexico considering exclusively the demand that it is generated by the air service. For the preliminary outline of the potential routes, that supports some estimates, a geographic information system was used. It was determined that there is potential of ten train routes for middle–speed trains and eight train routes for high-speed trains. It is possible to transport in these routes more than four million people annually. In addition, it was detected that these new services would provide other benefits, for instance, in environmental terms the middle and high–speed trains could reduce annually the emission of 213 kt and 248 kt of CO2 respectively. Also, it was determined that these services could postpone four more years the complete saturation of the Mexico City International Airport; and that the routes equipped for the highspeed service require 27 times higher investments than the middle-speed service

Comparative study of autonomous path-following vehicle control via model predictive control and linear quadratic control

This paper describes a comparative study of steering and yaw moment control manoeuvres in the model predictive control and linear quadratic control approaches for path-following control of an autonomous vehicle. We present the effectiveness of the model predictive control and linear quadratic control approaches for stability control of the vehicle’s lateral position and yaw angle for different control manoeuvres: two-wheel steering, four-wheel steering and direct yaw moment control. We then propose model predictive control with a feedforward controller to minimize the tracking errors of the lateral position and the yaw angle in an active front steering manoeuvre, and these are compared with the results from linear quadratic control that has a feedforward controller. Model predictive control is designed on the basis of the simple yaw–lateral motions of a single-track vehicle with a linear tyre model (i.e. a bicycle model), which is an approximation of the more realistic model of a vehicle with double-track yaw–roll motion with a non-linear tyre model (i.e. the Pacejka model). The linear quadratic controller is designed on the basis of the same approach as adopted for the model predictive controller to achieve a fair comparison. On the basis of a given trajectory, we simulate the manoeuvre of the vehicle at a low speed, a middle speed and a high speed because load transfer effects will influence the roll dynamics especially at a high speed. We also perform simulations on low-road-friction surfaces in a double-lane-change scenario with the aim of following the desired trajectory as closely as possible while maintaining the vehicle stability. The simulation results show that model predictive control through two-wheel steering and four-wheel steering with direct yaw moment control performed better in terms of trajectory tracking at a high forward speed and low road surface variation. The proposed model predictive control with a feedforward controller is shown to be effective in minimizing the trajectory tracking errors. For all control manoeuvres, model predictive control gives a better tracking performance than linear quadratic control does. In addition, when the roll dynamics are considered, model predictive control significantly improves the vehicle stability and the trajectory along the desired path.

중질 잔사유의 연소성 분석과 보조 분사에 의한 연소성 향상에 관한 검토

Due to the development of the petroleum refining technology and continuously increased demand from markets, a quantity of gasoline and diesel oil produced from a restricted quantity of crude oil has been increasing, and residual fuel to be used at marine diesel engines has been gradually becoming low quality. As a result, it was recently reported that trouble oils which cause abnormal combustion such as knocking with extreme noise and misfire from internal combustion engines were increasing throughout the world. In this study, an author investigated ignitability and combustion quality by using combustion analyzer with constant volume(FCA, Fuel Combustion Analyzer) and middle speed diesel engine about MDO(Marine Diesel Oil), HFO(Heavy Fuel Oil), LCO(Light Cycle Oil) and Blend-HFO which was blended LCO of 1000 liters with HFO of 600 liters. Moreover, for betterment of ignitability and combustion quality of injected fuels, multi-injection experiment was carried out in the diesel engine using Blend-HFO. According to the results of FCA analysis, ignitability and combustion quality was bad in the order of MDO<HFO<Blend-HFO<LCO. And combustion of blended HFO caused extreme knocking in experiments of the diesel engine. However, sub-injection with injection timing of BTDC 20 CA(Crack Angle) defused the knocking that was caused from drop of fuel quality.

Experimental investigation on diesel engine’s waste heat capacity under mapping characteristics

Waste heat recovery for internal combustion engine (ICE) has been considered as an important strategy to improve efficiency and promote fuel economy, thus alleviating the problems of energy shortage and environmental pollution. This paper investigates the characteristics of various kinds of waste heat energy, namely, waste heat in exhaust, cooling water and charge air, over the engine’s whole operating region. Based on the energy balance experiments, the energy distribution of a conventional heavy-duty diesel engine is obtained under mapping characteristics. According to exergy analysis, the energy recovery potential for waste heat is studied as well. The experimental results indicate that exhaust energy increases with engine speed and load, while cooling water energy is more sensitive to load, especially at low and middle speed. Charge air energy, on the other hand, mainly counts on speed rather than load. Exhaust energy possesses the highest recovery potential in terms of both quantity and quality. Through waste heat recovery, a dramatic improvement in engine efficiency is achievable, actually, the maximum value can amount to 60% or even more.

Influence of Passenger Load on Diesel Bus Emissions

The purpose of this paper is to analyze the influence of passenger load on diesel bus emissions based on the real-world on-road emission data collected by the Portable Emission Measurement System (PEMS). It is also analyzed whether passenger load affect the accuracy of emission models based on VSP. The results indicate that the influence of passenger load on emission rates of CO2, CO, NOX and HC is various with different speed and acceleration ranges. As for the distance-based emission factors of CO2, CO, NOX and HC, per-passenger emission factors decrease with the rise of passenger load. In addition, it is found that the influence of passenger load can be omitted properly in the emission models of low and middle speed bins. But that can lead to an error reaching up to 49% if the influence of passenger load is neglected in the models of high speed bins.

Lower rotation speed stimulates sympathetic activation during continuous-flow left ventricular assist device treatment.

Although the suppression of sympathetic activity is an essential mission for the current heart failure treatment strategy, little is known about the relationship between the rotation speed setting and autonomic nervous activity during continuous-flow left ventricular assist device (LVAD) treatment. We evaluated 23 adult patients with sinus rhythm (36 ± 13 years) who had received continuous-flow LVAD and been followed at our institute between March 2013 and August 2014. Heart rate variability measurement was executed along with hemodynamic study at 3 rotation speeds (low, middle, and high) at 5 weeks after LVAD implantation. Lower rotation speed was associated with higher ratio of low-frequency over high-frequency spectral level (LF/HF), representing enhanced sympathetic activation (p < 0.05 by repeated analyses of variance). Among hemodynamic parameters, cardiac index was exclusively associated with LFNU = LF/(LF + HF), representing relative sympathetic activity over parasympathetic one (p < 0.05). After 6 months LVAD support at middle rotation speed, 19 patients with higher LFNU eventually had higher plasma levels of B-type natriuretic peptide and achieved less LV reverse remodeling. A logistic regression analysis demonstrated that lower LFNU was significantly associated with improvement of LV reverse remodeling (p = 0.021, odds ratio 0.903) with a cut-off level of 55 % calculated by the ROC analysis (AUC 0.869). In conclusion, autonomic activity can vary in various rotation speeds. Patients with higher LFNU may better be controlled at higher rotation speed with the view point to suppress sympathetic activity and achieve LV reverse remodeling.

Analysis of the Sensorless PMSM Control Technique in the Full Speed Section

A novel position sensorless control strategy integrated with full section and high precision for a permanent magnet synchronous motor (PMSM) applied to wind power pitch was proposed in the paper. Based on high frequency signal, where three-phase triangular carrier spwm is injected and the state current response is detected to accurately estimate the rotor position in the still and low speed, which doesn’t rely on the non-ideal features. Based on BEF PMSM mathematic model, the phase locked loop technique is used to accurately detect the rotor position in the middle and high speed. the Finally, experiment on a 10 KW pith system demonstrates that the proposed method is effective and is capable of achieving more accurate control in the full speed section.