Three-dimensional Dynamic Simulation Model Research Articles

Evaluation of Ground Pressure, Bearing Capacity, and Sinkage in Rigid-Flexible Tracked Vehicles on Characterized Terrain in Laboratory Conditions.

Trafficability gives tracked vehicles adaptability, stability, and propulsion for various purposes, including deep-sea research in rough terrain. Terrain characteristics affect tracked vehicle mobility. This paper investigates the soil mechanical interaction dynamics between rubber-tracked vehicles and sedimental soils through controlled laboratory-simulated experiments. Focusing on Bentonite and Diatom sedimental soils, which possess distinct shear properties from typical land soils, the study employs innovative user-written subroutines to characterize mechanical models linked to the RecurDyn simulation environment. The experiment is centered around a dual-tracked crawler, which in itself represents a fully independent vehicle. A new three-dimensional multi-body dynamic simulation model of the tracked vehicle is developed, integrating the moist terrain's mechanical model. Simulations assess the vehicle's trafficability and performance, revealing optimal slip ratios for maximum traction force. Additionally, a mathematical model evaluates the vehicle's tractive trafficability based on slip ratio and primary design parameters. The study offers valuable insights and a practical simulation modeling approach for assessing trafficability, predicting locomotion, optimizing design, and controlling the motion of tracked vehicles across diverse moist terrain conditions. The focus is on the critical factors influencing the mobility of tracked vehicles, precisely the sinkage speed and its relationship with pressure. The study introduces a rubber-tracked vehicle, pressure, and moisture sensors to monitor pressure sinkage and moisture, evaluating cohesive soils (Bentonite/Diatom) in combination with sand and gravel mixtures. Findings reveal that higher moisture content in Bentonite correlates with increased track slippage and sinkage, contrasting with Diatom's notable compaction and sinkage characteristics. This research enhances precision in terrain assessment, improves tracked vehicle design, and advances terrain mechanics comprehension for off-road exploration, offering valuable insights for vehicle design practices and exploration endeavors.

Design and Optimization of a Robot Dosing Device for Aliquoting of Biological Samples Based on Genetic Algorithms

Aliquoting of biological samples refers to the process of dividing a larger biological sample into smaller, representative portions known as aliquots. This procedure is commonly employed in laboratories, especially in fields like molecular biology, genetics, and clinical research. Currently, manual dosing devices are commonplace in laboratories, but they demand a significant amount of time for their manual operation. The automated dosing devices available are integrated into narrowly focused aliquoting systems and lack versatility as manipulator equipment. Addressing this limitation, a novel technical solution is proposed in this paper for a modular dosing device compatible with robotic manipulators. The paper introduces and details a mathematical model, optimizes its parameters, and constructs a detailed 3D model using the NX environment to demonstrate the engineering feasibility of our concept. It further outlines the development of a three-dimensional dynamic simulation model for the dosing device, comparing analytical calculations with simulation results. The construction of a dosing device prototype is discussed, followed by a comprehensive experimental validation.

Computational Investigation of Combustion, Performance, and Emissions of a Diesel-Hydrogen Dual-Fuel Engine

This paper aims to expose the effect of hydrogen on the combustion, performance, and emissions of a high-speed diesel engine. For this purpose, a three-dimensional dynamic simulation model was developed using a reasonable turbulence model, and a simplified reaction kinetic mechanism was chosen based on experimental data. The results show that in the hydrogen enrichment conditions, hydrogen causes complete combustion of diesel fuel and results in a 17.7% increase in work capacity. However, the increase in combustion temperature resulted in higher NOx emissions. In the hydrogen substitution condition, the combustion phases are significantly earlier with the increased hydrogen substitution ratio (HSR), which is not conducive to power output. However, when the HSR is 30%, the CO, soot, and THC reach near-zero emissions. The effect of the injection timing is also studied at an HSR of 90%. When delayed by 10°, IMEP improves by 3.4% compared with diesel mode and 2.4% compared with dual-fuel mode. The NOx is reduced by 53% compared with the original dual-fuel mode. This study provides theoretical guidance for the application of hydrogen in rail transportation.

Implementation of a novel dual-layer machine learning structure for predicting the intake characteristics of a side-ported Wankel rotary engine

This paper aims to predict the intake characteristics of a side-ported Wankel rotary engine implemented by a novel dual-layer machine learning (ML) structure. The Sobol sequence coupled with a parametric phase control model is performed to generate samples using a three-dimensional dynamic simulation model. Two ML structures are compared to determine the input features, in which the input features of structure A are the port phases, while structure B also contains the geometric features. Compared with Structure A, the regression and generalization abilities of Structure B with different ML methods are generally favorable. Based on structure B, a novel dual-layer structure prediction model is developed using the Gaussian process regression method in which geometric features are used as intermediate variables. The results show that for the prediction of intake loss and volumetric efficiency, the coefficients of determination are greater than 0.99, and the prediction error is less than 1%. In addition, the port full closing timing determines the intake characteristics compared with other port phases. This paper provides novel solutions for predicting intake characteristics to guide practical optimization.

A CFD Validation Effect of YP/PV from Laboratory-Formulated SBMDIF for Productive Transport Load to the Surface

Several technical factors contribute to the flow of cuttings from the wellbore to the surface of the well, some of which are fundamentally due to the speed and inclination of the drill pipe at different positions (concentric and eccentric), the efficacy of the drilling mud considers plastic viscosity (PV) and yield point (YP), the weight of the cuttings, and the deviation of the well. Moreover, these overlaying cutting beds breed destruction in the drilling operation, some of which cause stuck pipes, reducing the rate of rotation and penetration. This current study, while it addresses the apropos of artificial intelligence (AI) with symmetry, employs a three-dimensional computational fluid dynamic (CFD) simulation model to validate an effective synthetic-based mud-drilling and to investigate the potency of the muds’ flow behaviours for transporting cuttings. Furthermore, the study examines the ratio effects of YP/PV to attain the safe transport of cuttings based on the turbulence of solid-particle suspension from the drilling fluid and the cuttings, and its velocity–pressure influence in a vertical well under a concentric and eccentric position of the drilling pipe. The resulting CFD analysis explains that the YP/PV of SBM and OBM, which generated the required capacity to suspend the cuttings to the surface, are symmetric to the experimental results and hence, the position of the drill pipe at the concentric position in vertical wells required a lower rotational speed. A computational study of the synthetic-based mud and its potency of not damaging the wellbore under an eccentric drill pipe position can be further examined.

Combined Effect of Air Intake Method and Hydrogen Injection Timing on Airflow Movement and Mixture Formation in a hydrogen direct injection rotary engine

The hydrogen rotary engine (HRE) has advantages of the high power-to-weight ratio and low emission performance. In this study, a three-dimensional dynamic simulation model of the hydrogen direct injection rotary engine is established, and the accuracy and reliability of the gas nozzle injection model are verified based on experimental data in detail. Then, the combined effects of the air intake method (AIM) and hydrogen injection timing (HIT) on airflow movement and mixture formation processes in the HRE are investigated. The numerical results show that the compound AIM improves the engine volumetric efficiency due to more air entering. As for air movement, the average airflow velocity and turbulent kinetic energy both increase significantly during hydrogen injection duration under different HITs and AIMs. In terms of mixture formation, using compound AIM, more hydrogen accumulates near the ignition chamber compared to the peripheral and side AIMs. Also, when HITs are −286°CA and −190°CA, hydrogen concentrates near the ignition chamber, which will be conducive to the subsequent combustion process due to the RE's flame forward propagation characteristics. Comprehensively considering the airflow movement characteristics and fuel distribution rule, the peripheral AIM and the compound AIM, which their HITs are set at the compression stage (−190°CA), namely Case7 and Case9, are preferred schemes. This paper can provide some theoretical guidance for the intake structure design, injection strategy optimization and mixture rational organization of the HRE. • Airflow movement and mixture formation of a hydrogen rotary engine is explored. • The gas nozzle injection model is detailly validated based on experimental data. • Effect of air intake method and fuel injection timing on the flow process is studied. • Ideal schemes (Case7 and Case9) are obtainedby analyzing fuel distribution rules.

Combined effect of intake angle and chamber structure on flow field and combustion process in a small-scaled rotary engine

This work aims to reveal combined effect of intake angle and chamber structure on flow field, flame propagation, combustion characteristics and pollutants formation of a small-scaled rotary engine by using numerical simulation. For this reason, a three-dimensional dynamic simulation model was established by using a reasonable turbulent model and choosing a reduced reaction kinetic mechanism and was also validated by the experimental data. Simulation results showed that intake angle is more significant to the influence of flame propagation, in-cylinder pressure and heat release rate (HRR) in the front baffle combustion chamber (FBCC) and the rear baffle combustion chamber (RBCC) compared to that in the middle baffle combustion chamber (MBCC), but is an opposite trend for effect of flow field. The differences in the in-cylinder velocity field and turbulent kinetic energy magnitude were the intrinsic mechanism of combined influence of intake angle and chamber structure. Under larger intake angle, for the MBCC and the RBCC, higher pressure, HRR and power output were obtained, meanwhile the decreased HC and CO formations were obtained, while showed a contrary tend for the FBCC. And the amount of HC formation for these three combustion chambers at 15°intake angle is relatively small. To sum up, considering combustion characteristics, engine cooling and pollutants formation, it can be concluded that the combination of 15°intake angle and combustion chamber with a middle baffle was the optimum configuration for a small-scaled RE in engineering application. • The recess shape of rotor and intake angle are optimized. • Intake angle is more significant to the influence of combustion in FBCC and RBCC. • Recess shape plays a more significant role in effect of flow field and combustion. • Larger flow velocity and TKE near the spark plugs improve initial flame development. • The optimal scheme is the combination of 15° intake angle and MBCC or RBCC.

Effect analysis of the forward flow fuel injection angle on stratified combustion process in a high-pressure direct injection diesel Wankel engine (HPDI-DWE)

High-pressure direct injection (HPDI) combined with stratified combustion technology can further enhance the combustion performance of the diesel Wankel engine (DWE). Consequently, based on our experimentally validated three-dimensional (3D) dynamic simulation model, this study proposes to adopt the fine-designed forward flow fuel injection angle (FIA) to realize mixture distribution in the front region of the rotary combustion chamber (RCC). Then the stratified fuel movement and combustion processes under different FIAs of a high-pressure direct injection diesel Wankel engine (HPDI-DWE) are investigated. The numerical results show that for mixture formation, the ideal distribution rule should make the fuel distribute near the spark ignition chamber (SIC) and avoid excessive mixture concentration since flame presents forward propagation characteristics. During the combustion process, combustion reaction occurs in the front zone of the RCC, while flame front shapes show symmetry structure due to the stratified distribution of fuel and generation of symmetric vortexes in this region. Increasing FIA, better power performance is obtained overall, meanwhile, mixture combustion rate and heat release process are accelerated. Considering the trade-off between power and emission, the preferred FIA is 65°. Compared to FIA of 60° (original scheme), its peak pressure (Pmax) is increased by 1.8%, total combustion duration (TCD), central heat release angle (CA50) and flame propagation period (CA10-90) are shortened by 11.1%, 20.4% and 14.1%, respectively. Moreover, soot and carbon dioxide (NO) are significantly reduced by 39.5% and 52.5%, respectively.

Experimental and Numerical Study on the Formation Mechanism of Flow Field in a Side-Ported Rotary Engine Considering Apex Seal Leakage

Abstract The aim of this research is to investigate the influences of apex seal leakage on the formation mechanism of flow field in a side-ported rotary engine by particle image velocimetry (PIV) and computational fluid dynamics (CFD). In this study, a PIV was used to acquire the two-dimensional (2D) flow field on the rotor housing central plane at an engine speed of 700 rpm. A three-dimensional (3D) dynamic simulation model considering leakage through apex seals was established and verified by the 2D-PIV experiment results. Thereafter, CFD analysis was used to further understand the 3D flow field in combustion chamber under the action of apex seal leakage. The simulation results showed that for the three engine speeds (2000, 3500, and 5000 rpm), in the intake stroke, the vortex generated in the front end of combustion chamber under the condition with no leakage, was strengthened and destroyed by the effects of the small (0.02 mm) and the large (0.08 mm) apex seal leakage gaps, respectively. As the apex seal leakage gap increased, the volume efficiency and the peak pressure decreased continuously. The volume efficiency and the peak pressure caused by any fixed apex seal leakage gap decreased with the increase of the engine speed. Compared with the volumetric efficiency of the condition with no leakage at 2000 and 5000 rpm, the volumetric efficiency of apex seal leakage gap of 0.08 mm decreased only by 24.6% at 5000 rpm, but by 41.2% at 2000 rpm.

Analysis on the Performance Improvement of Reciprocating Pump with Variable Stiffness Valve using CFD

As a key component of reciprocating pump, the valve has a significant influence on its performance. However, it is difficult for the existing valve to simultaneously solve the problems such as fatigue, erosion and cavitation in engineering application. In this paper, a solution to these problems of using variable stiffness spring is proposed. And three new structures of the valve are designed. Furthermore, based on Computational Fluid Dynamics (CFD) method, a three-dimensional dynamic simulation model considering fluid-structure interaction in the suction stroke of reciprocating pump is established by using dynamic grid technique and User-Defined Functions (UDF). The performance of these new valves are compared with that of conventional valve respectively. The result shows that the new valves have significant influence on the motion characteristics of the valve disc, flow field distribution and cavitation. Besides, the simulation and experimental results of the maximum lift are compared, and it is found that they are basically in agreement. The new structures provide a new research direction for improving the performance of reciprocating pump. Simultaneously, the above simulation method can also provide guidance for valve design, structural optimization and service life improvement.

Research on the application of aviation kerosene in a direct injection rotary engine – Part 2: Spray combustion characteristics and combustion process under optimized injection strategies

Investigating the adaptability of aviation kerosene in the direct injection rotary engine is of great significance and practical value. In this paper, an optically visible constant volume combustion chamber platform with various optical diagnostic techniques was firstly set up to study the spray combustion characteristics of the fuel. Secondly, a reliable three-dimensional dynamic simulation model of direct injection rotary engine was established to investigate the combustion process of aviation kerosene under optimized injection strategies. The experimental results show that the ambient temperature of 800 K and ambient pressure of 20 bar is the ignition limit of aviation kerosene under the condition of rotary engine. With the increase of ambient conditions, the ignition delay and the flame lift-off length shorten continuously. At 850 K ambient temperature, when the ambient pressure reaches 25 bar, the lift-off length will no longer shorten and remains at about 6 mm. The simulation results indicate that under the Injection position A-Injection angle 90° (Case A3), higher combustion efficiency before top dead center can be achieved due to more appropriate distribution, concentration and atomization quality of fuel at ignition timing. The peak pressure in cylinder reaches 38.89 bar, which means a better engine dynamic performance. Meanwhile, acceptable CO and Soot emissions are obtained by the complete combustion of fuel in Case A3, however, the higher combustion temperature makes the production of pollutant NO slightly higher than other injection strategies.

Study on improving three-dimensional dynamic simulation model and equation of flexible fabric

The use of the traditional fabric simulation model evidently shows that it cannot accurately reflect the material properties of the real fabric. This is against the background that the simulation result is artificial or an imitation, which leads to a low simulation equation. In order to solve such problems from occurring, there is need for a novel model that is designed to enhance the essential properties required for a flexible fabric, the simulation effect of the fabric, and the efficiency of simulation equation solving. Therefore, the improvement study results will offer a meaningful and practical understanding within the field of garment automation design, three-dimensional animation, virtual fitting to mention but a few.

Research on the application of aviation kerosene in a direct injection rotary engine-Part 1: Fundamental spray characteristics and optimized injection strategies

In view of the gradual promotion of Single Fuel Concept in the military field and also the rotary engine (RE) which has been widely applied in specialized equipment, it is necessary to study the basic spray characteristics of aviation kerosene under RE operation conditions and optimize the fuel injection strategies. In this research, an optically visible constant volume combustion chamber platform for Mie-scattering and a validated three-dimensional dynamic simulation model of aviation kerosene fueled direct injection rotary engine (DI-RE) were established. The experimental results show that the ambient temperature and pressure affect the spray process differently. There is no linear relationship between ambient temperature and penetration length. The ambient temperature of 600 K is a watershed, when it is below 600 K, the penetration length increases as the temperature rises. When the temperature reaches 600 K, the penetration length decreases rapidly which means a prominent improvement of atomization quality. On the basis of experimental results, the simulation was carried out and the results show that different injection strategies have important effect on distribution of fuel in cylinder, the larger injection angle will promote the atomization of fuel due to the collision between the spray and air flow field. In Case A3, B2 and C2, the fuel mainly distributes near the spark plugs in the center of the combustion chamber, which is supposed to be more conducive to the ignition and diffusion combustion process of the fuel.

Effect of dual-spark plug arrangements on ignition and combustion processes of a gasoline rotary engine with hydrogen direct-injection enrichment

A gasoline rotary engine enriched with directly injected hydrogen could be regarded as an appealing option to improve combustion efficiency while reducing emissions. In this paper, a three-dimensional dynamic simulation model coupling with the chemical kinetic mechanisms was established using CONVERGE software and validated by the experimental data. The numerical model was implemented for evaluating the influences of varying duel-spark plug locations on flow field distributions, combustion processes and major emissions formation of a gasoline rotary engine with hydrogen direct injection enrichment. Simulation results showed that, a mainstream flow field formed during the end period of the compression stoke whose direction was identical to the rotor rotating direction. The variation of trailing-spark plug location resulted in slight influence on the mean flow velocity as well as notable impact on hydrogen concentration and turbulent kinetic energy distribution. It was conducive to initial ignition when the local equivalence ratio was intensified near the duel-spark plug on the leading side of the combustion chamber. Higher hydrogen concentration near spark plugs could effectively improve the combustion intensity. The preferable combustion and emission performance were achieved when the duel-spark plug positioned symmetrically with respect to the minor axis. Compared with the scheme of the closest duel-spark plug, the peak pressure increased by 24.4% and corresponding crank position advanced by 9.2°CA. Despite nitric oxides emissions increased slightly, carbon monoxide emission notably reduced by 57.6% versus the scheme of the farthest duel-spark plug. When the leading-spark plug remained constant, the trailing-spark plug arranged on the major axis of cylinder wall and kept an appropriate offset from the minor axis was recommended in engineering applications.

Numerical study of hydrogen direct injection strategy on mixture formation and combustion process in a partially premixed gasoline Wankel rotary engine

In Wankel rotary engine (WRE), high mainstream velocity in combustion chamber blocks flame propagating to the end of combustion chamber, which causes high emissions and low combustion efficiency due to unburned mixtures. To solve this problem, a three-dimensional dynamic simulation model of a hydrogen-gasoline blends fueled WRE is built and validated. The in-cylinder mixture formation and combustion process are investigated under different hydrogen injection timing (HIT) and duration (HID) conditions. The study results show that the concentration of hydrogen distributed between the spark plug region and rear combustion chamber increases with retarded HIT and extended HID. Faster flame speeds are obtained for HIT of 110 °CA BTDC and HID of 40 °CA. At a fixed HID of 20 °CA, compared with HITs of 210 and 160 °CA BTDC, the peak in-cylinder pressures for HIT of 110 °CA BTDC are increased by 14.3% and 6.8%, respectively. At a fixed HIT of 110 °CA BTDC, the peak in-cylinder pressure in HID of 40 °CA is 52.3% and 9.21% higher than HIDs of 20 and 30 °CA. The highest in-cylinder pressure is achieved with the hydrogen injection strategy that HIT of 110 °CA BTDC, HID of 40 °CA. However, as the temperature increases with pressure, nitrogen oxide emissions are also increased with retarded HIT and extended HID obviously. Considering the lowest carbon monoxide is achieved and the unburned zone in the rear region of combustion chamber is eliminated in HIT of 110 °CA BTDC, HID of 40 °CA. The hydrogen direct injection strategy that HIT of 110 °CA BTDC, HID of 40 °CA acquires the best engine performance in this research.

Effects of hydrogen blending mode on combustion process of a rotary engine fueled with natural gas/hydrogen blends

The highly advanced wankel rotary engine is a promising energy system because of its favorable energy to weight ratio, multi-fuel capability and large specific power output. This work aims to numerically study the performance, combustion and emission characteristics of a side-ported rotary engine fueled with natural gas/hydrogen blends under different hydrogen blending modes. Simulations were performed using multi-dimensional software FLUENT 14.0. On the basis of the software, a three-dimensional dynamic simulation model was established by writing dynamic mesh programs, choosing the RNG k-ε turbulent model, the eddy-dissipation concept (EDC) combustion model and a reduced reaction mechanism. The three-dimensional dynamic simulation model based on the chemical reaction kinetics was also validated by the experimental data. Meanwhile, further simulations were then conducted to investigate how to impact the combustion process by the coupling function between hydrogen distribution and the flow field inside the cylinder. Simulation results showed that in order to improve the combustion efficiency, the low-pressure early injection should be used as the hydrogen blending mode. The low-pressure early injection, not only allowed the hydrogen in the combustion chamber to be distributed evenly, but also resulted in the high concentration areas of hydrogen located at the front of the trialing spark plug, which can be used to increase the combustion rate. For the hydrogen low-pressure early injection, the improved combustion rate made in-cylinder pressure and the intermediate OH increase significantly. Compared with no hydrogen induction, it shows a 29% increase in the peak pressures. Meanwhile, the drawback is the increase in NO emissions.

Effects of ignition parameters on combustion process of a rotary engine fueled with natural gas

The side-ported rotary engine fueled with natural gas is anew,clean,efficientenergy system. This work aims to numerically study the performance, combustion and emission characteristics of a side-ported rotary engine fueled with natural gas under different ignition positions andignition timings. Simulations were performed using multi-dimensional software ANASYS Fluent. Onthebasisof the software, a three-dimensional dynamic simulation model was established by writing dynamic mesh programs and choosing a detailed reaction mechanism. The three-dimensional dynamic simulation model, based on the chemical reaction kinetics, was also validated by the experimental data. Meanwhile, further simulations were then conducted to investigate how to impact the combustion process by the couplingfunction between ignitionoperating parameter and the flow field inside the cylinder. Simulation results showed that in order to improve the combustion efficiency, the trailing spark plugshould be located at the rear of the tumble zone and the ignition timing should be advanced properly. This was mainly caused by the trailing spark plug being located at the rear of the tumble zone, as it not only allowed the fuel in the rear of combustion chamber to be burnt without delay, but also permitted the acceleration of the flame propagation by the tumble. Meanwhile, with advanced ignition timing, the time between ignitiontiming and the timing of the tumble disappearance increased, which led to an increase of the tumble effect time used to improve the combustion rate. However, the drawback of this improved combustion was the slight increase in NO emissions. Under thecomputationalcondition, when the trailing spark plug scheme of case C coupled with an ignition timing of 50°CA (BTDC) was compared with the spark plug location and the ignition timing of theoriginalengine, it showed a27.4% increasein thepeak pressure. Taking the limited increaseof NO exhaust into consideration it was thebest ignitionallocation scheme under thecomputational condition. This study provided a theoretical foundation for the determination of best ignition position and ignition timing under different working conditions.

Effects of pocket shape and ignition slot locations on the combustion processes of a rotary engine fueled with natural gas

This work aims to numerically study the performance, combustion and emission characteristics of a side-ported natural-gas-fueled rotary engine under different pocket shapes and ignition slot positions. Simulations were performed using multi-dimensional software FLUENT 14.0. On the basis of the software, a three-dimensional dynamic simulation model was established by writing dynamic mesh programs and choosing a detailed reaction mechanism. The three-dimensional dynamic simulation model, based on the chemical reaction kinetics, was also validated by the experimental data. Simulation results showed that a bigger intensity of the tumble, a larger area of the high speed oblique flow and a higher average flow speed in the middle of the combustion chamber can make the flame propagation speed increase. When the combustion chamber configuration had a middling pocket coupled with an ignition slot located at the middle of the width direction of rotor surface, the combustion rate is the highest. As a result, the cylinder pressure and the intermediate OH increased significantly. Compared with the combustion chamber configuration, which had a flat-top pocket without ignition slot, it showed a 10 percent increase in the peak pressures, but a certain increase in NO emissions.

Experimental and numerical investigation of the fluid flow in a side-ported rotary engine

The side-ported rotary engine is a potential alternative to the reciprocating engine because of its favorable performance at low speed. The performance of side-ported rotary engines is strongly influenced by the flow field in the combustion chamber. In this study, an optical side-ported rotary engine test-bed was built and PIV was employed to measure the flow field in the rotor housing central plane. From experiment results, a counterclockwise swirl was detected in the rotor housing central plane. Meanwhile, a three-dimensional dynamic mesh and turbulent flow model was integrated and simulated using the Fluent CFD software. The three-dimensional dynamic simulation model was validated by comparison with experimental results. In addition, the effect of three major parameters on the flow field in the combustion chamber, namely rotating speed, intake pressure and intake angle were numerically investigated. The results show that a swirl forms in the middle and front of the combustion chamber during the intake stroke under low rotating speed. This is in line with the swirl detected in the rotor housing central plane though the PIV experiment at 600rpm. Furthermore, the flow field, volume coefficient and average turbulence kinetic energy in the combustion chamber were studied in detail by varying rotating speed, intake pressure and intake angle.

Influence of Combustion Chamber Configuration on Combustion Process of Natural Gas-fueled Rotary Engines

Taking a side ported pre-mixed natural gas-fueled rotary engine converted from a gasoline rotary engine as the study object. On the basis of the Fluent simulation software, a three-dimensional dynamic simulation model is established by writing dynamic mesh programs and choosing the reasonable turbulent model, combustion model, CHEMKIN mechanism. The three-dimensional dynamic simulation model based on the chemical reaction kinetics is also validated by the experimental data. On this basis, the three-dimensional dynamic characteristics for flow, temperature field and the combustion intermediate product under different combustion chamber configuration are analyzed. The results show that when the rotor pocket is located at the front end of rotor surface along length direction and the center of the rotor surface along width direction, a tumble in the rear of combustion chamber and a high speed flow in the middle of combustion chamber are made full use to increase flame speed. The flame propagation speed reaches the maximum value. The indicator diagram is best and the production of OH is biggest. Comparing with mid pocket combustion chamber, the front pocket combustion chamber shows a 19.9 percent increase in the peak pressures, but NO emission mass fraction still stay within 0.5 percent.