The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform

David L Reuss - One of the best experts on this subject based on the ideXlab platform.

  • the role of spray enhanced swirl flow for combustion stabilization in a stratified charge disi engine
    Combustion and Flame, 2016
    Co-Authors: Wei Zeng, David L Reuss, Magnus Sjoberg
    Abstract:

    Abstract Implementation of spray-guided stratified-charge direct-injection spark-ignited (DISI) engines is inhibited by the occurrence of misfire and partial burns. Engine-performance tests demonstrate that increasing engine speed induces combustion instability, but this deterioration can be prevented by generating swirling flow during the Intake Stroke. In-cylinder pressure-based heat-release analysis reveals that the appearance of poor-burn cycles is not solely dependent on the variability of early flame-kernel growth. Cycles can experience burning-rate regression during later combustion stages and may or may not recover before the end of the cycle. Thermodynamic analysis and optical diagnostics are used here to clarify why swirl improves the combustion repeatability from cycle to cycle. The fluid dynamics of swirl/spray interaction was previously demonstrated using high-speed PIV measurements of in-cylinder motored flow. It was found that the sprays of the multi-hole injector redistribute the Intake-generated swirl flow momentum, thereby creating a better-centered higher angular-momentum vortex with reduced variability. The engine operation with high swirl was found to have significant improvement in cycle-to-cycle variations of both flow pattern and flow momentum. This paper is an extension of the previous work. Here, PIV measurements and flame imaging are applied to fired operation for studying how the swirl flow affects variability of ignition and subsequent combustion phases. PIV results for fired operation are consistent with the measurements made of motored flow. They demonstrate that the spark-plasma motion is highly correlated with the direction of the gas flow in the vicinity of the spark-plug gap. Without swirl, the plasma is randomly stretched towards either side of the spark plug, causing variability in the ignition of the two spray plumes that are straddling the spark plug. In contrast, swirl flow always convects the spark plasma towards one spray plume, causing a more repeatable ignition. The swirl decreases local RMS velocity, consistent with an observed reduction of early-burn variability. Broadband flame imaging demonstrates that with swirl, the flame consistently propagates in multiple directions to consume fuel–air mixtures within the piston bowl. In contrast, operation without swirl displays higher variability of flame-spread patterns, occasionally causing the appearance of partial-burn cycles.

Baowei Fan - One of the best experts on this subject based on the ideXlab platform.

  • effect of hydrogen injection strategies on mixture formation and combustion process in a hydrogen direct injection plus natural gas port injection rotary engine
    Energy Conversion and Management, 2018
    Co-Authors: Baowei Fan, Jianfeng Pan, Zhenhua Pan, Yuejin Zhu, Wei Chen, Yangxian Liu, Peter Otchere
    Abstract:

    Abstract This work aimed to numerically study the effect of hydrogen injection strategies on mixture formation and combustion process in a hydrogen direct injection plus natural gas port injection (HDI + NGPI) rotary engine. Two major factors, namely hydrogen injection timing (HIT) and hydrogen injection angle (HIA), were considered. Four HITs which were used in simulation, were from the early stages of Intake Stroke to the late stages of compression stoke. Comparing the fuel movement and combustion process among the four HITs with three HIAs (−60°, 0° and 60°), it was found that for hydrogen movement, when the HIT was at early stages of Intake Stroke, this advanced HIT led to the fact that the hydrogen distribution areas at ignition timing all spread across the whole combustion chamber for all three HIA cases. When the HIT was at the late stages of the Intake Stroke and the whole compression Stroke, with an increased hydrogen injection angle (HIA) (from −60°, 0° to 60°), the hydrogen accumulation area moved from the front towards the rear of combustion chamber. In addition, with retarded HIT, the hydrogen aggregation degree increased continuously. For combustion process, to obtain a higher overall combustion rate, the hydrogen injection strategy should make as much hydrogen spread between the two spark plugs at ignition timing. In addition, the hydrogen concentration near the LSP and the TSP should be conducive to the flame kernel formation. This is mainly because of the fact that the above hydrogen distributions, not only lead to the rapid formation of the flame kernel near the LSP and the TSP, but also make use of the hydrogen at the early stage of combustion Stroke. Under the computational condition, the overall combustion rate for case A: 140 − 60 which had a HIT of 140°CA (BTDC) and a HIA of −60°CA, was the fastest. Compared with case C: 300 + 60 which had a HIT of 300°CA (BTDC) and a HIA of 60°CA, the peak pressure of case A: 140 − 60 was raised by 31.1%. However, compared with other cases, the NO emissions of case A: 140 − 60 at 80°CA (ATDC) was the maximum. Furthermore, for engineering applications, this study also provided a scheme of the change of the optimum HIA under different HITs for improving the performance of the HDI + NGPI rotary engine.

  • combined effect of injection timing and injection angle on mixture formation and combustion process in a direct injection di natural gas rotary engine
    Energy, 2017
    Co-Authors: Baowei Fan, Jianfeng Pan, Zhenhua Pan, Wenming Yang, Stephen Bani, Wei Chen
    Abstract:

    Abstract The application of direct injection (DI) technology is considered as a key solution to the problems of combustion efficiency and emissions on the rotary engine. This work aimed to numerically study the combined effect of injection timing (IT) and injection angle (IA) on mixture formation and combustion process in the 3D flow field of a DI natural gas rotary engine. On the basis of the 3D dynamic simulation model which was established in our previous work [29, 30], some critical information was obtained which was difficult to acquire through experiment. Simulation results showed that to satisfy the ideal fuel distribution for high combustion rate, a small IA should be used when the IT was at the early stages of Intake Stroke, and a big IA should be used when the IT was at the early stages of compression Stroke. However, when the IT was at the middle and later stages of Intake Stroke, the IA which could satisfy the ideal fuel distribution, was difficult to determine with the changed IT in the middle and later stage of Intake Stroke. For the above reason, the middle and late stage of Intake Stroke was not recommended as injection timing in engineering application.

  • experimental and numerical investigation of the fluid flow in a side ported rotary engine
    Energy Conversion and Management, 2015
    Co-Authors: Baowei Fan, Jianfeng Pan, Aikun Tang, Zhenhua Pan, Yuejin Zhu, Hong Xue
    Abstract:

    Abstract 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 600 rpm. 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.

Jianfeng Pan - One of the best experts on this subject based on the ideXlab platform.

  • effect of hydrogen injection strategies on mixture formation and combustion process in a hydrogen direct injection plus natural gas port injection rotary engine
    Energy Conversion and Management, 2018
    Co-Authors: Baowei Fan, Jianfeng Pan, Zhenhua Pan, Yuejin Zhu, Wei Chen, Yangxian Liu, Peter Otchere
    Abstract:

    Abstract This work aimed to numerically study the effect of hydrogen injection strategies on mixture formation and combustion process in a hydrogen direct injection plus natural gas port injection (HDI + NGPI) rotary engine. Two major factors, namely hydrogen injection timing (HIT) and hydrogen injection angle (HIA), were considered. Four HITs which were used in simulation, were from the early stages of Intake Stroke to the late stages of compression stoke. Comparing the fuel movement and combustion process among the four HITs with three HIAs (−60°, 0° and 60°), it was found that for hydrogen movement, when the HIT was at early stages of Intake Stroke, this advanced HIT led to the fact that the hydrogen distribution areas at ignition timing all spread across the whole combustion chamber for all three HIA cases. When the HIT was at the late stages of the Intake Stroke and the whole compression Stroke, with an increased hydrogen injection angle (HIA) (from −60°, 0° to 60°), the hydrogen accumulation area moved from the front towards the rear of combustion chamber. In addition, with retarded HIT, the hydrogen aggregation degree increased continuously. For combustion process, to obtain a higher overall combustion rate, the hydrogen injection strategy should make as much hydrogen spread between the two spark plugs at ignition timing. In addition, the hydrogen concentration near the LSP and the TSP should be conducive to the flame kernel formation. This is mainly because of the fact that the above hydrogen distributions, not only lead to the rapid formation of the flame kernel near the LSP and the TSP, but also make use of the hydrogen at the early stage of combustion Stroke. Under the computational condition, the overall combustion rate for case A: 140 − 60 which had a HIT of 140°CA (BTDC) and a HIA of −60°CA, was the fastest. Compared with case C: 300 + 60 which had a HIT of 300°CA (BTDC) and a HIA of 60°CA, the peak pressure of case A: 140 − 60 was raised by 31.1%. However, compared with other cases, the NO emissions of case A: 140 − 60 at 80°CA (ATDC) was the maximum. Furthermore, for engineering applications, this study also provided a scheme of the change of the optimum HIA under different HITs for improving the performance of the HDI + NGPI rotary engine.

  • combined effect of injection timing and injection angle on mixture formation and combustion process in a direct injection di natural gas rotary engine
    Energy, 2017
    Co-Authors: Baowei Fan, Jianfeng Pan, Zhenhua Pan, Wenming Yang, Stephen Bani, Wei Chen
    Abstract:

    Abstract The application of direct injection (DI) technology is considered as a key solution to the problems of combustion efficiency and emissions on the rotary engine. This work aimed to numerically study the combined effect of injection timing (IT) and injection angle (IA) on mixture formation and combustion process in the 3D flow field of a DI natural gas rotary engine. On the basis of the 3D dynamic simulation model which was established in our previous work [29, 30], some critical information was obtained which was difficult to acquire through experiment. Simulation results showed that to satisfy the ideal fuel distribution for high combustion rate, a small IA should be used when the IT was at the early stages of Intake Stroke, and a big IA should be used when the IT was at the early stages of compression Stroke. However, when the IT was at the middle and later stages of Intake Stroke, the IA which could satisfy the ideal fuel distribution, was difficult to determine with the changed IT in the middle and later stage of Intake Stroke. For the above reason, the middle and late stage of Intake Stroke was not recommended as injection timing in engineering application.

  • experimental and numerical investigation of the fluid flow in a side ported rotary engine
    Energy Conversion and Management, 2015
    Co-Authors: Baowei Fan, Jianfeng Pan, Aikun Tang, Zhenhua Pan, Yuejin Zhu, Hong Xue
    Abstract:

    Abstract 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 600 rpm. 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.

Zhenhua Pan - One of the best experts on this subject based on the ideXlab platform.

  • effect of hydrogen injection strategies on mixture formation and combustion process in a hydrogen direct injection plus natural gas port injection rotary engine
    Energy Conversion and Management, 2018
    Co-Authors: Baowei Fan, Jianfeng Pan, Zhenhua Pan, Yuejin Zhu, Wei Chen, Yangxian Liu, Peter Otchere
    Abstract:

    Abstract This work aimed to numerically study the effect of hydrogen injection strategies on mixture formation and combustion process in a hydrogen direct injection plus natural gas port injection (HDI + NGPI) rotary engine. Two major factors, namely hydrogen injection timing (HIT) and hydrogen injection angle (HIA), were considered. Four HITs which were used in simulation, were from the early stages of Intake Stroke to the late stages of compression stoke. Comparing the fuel movement and combustion process among the four HITs with three HIAs (−60°, 0° and 60°), it was found that for hydrogen movement, when the HIT was at early stages of Intake Stroke, this advanced HIT led to the fact that the hydrogen distribution areas at ignition timing all spread across the whole combustion chamber for all three HIA cases. When the HIT was at the late stages of the Intake Stroke and the whole compression Stroke, with an increased hydrogen injection angle (HIA) (from −60°, 0° to 60°), the hydrogen accumulation area moved from the front towards the rear of combustion chamber. In addition, with retarded HIT, the hydrogen aggregation degree increased continuously. For combustion process, to obtain a higher overall combustion rate, the hydrogen injection strategy should make as much hydrogen spread between the two spark plugs at ignition timing. In addition, the hydrogen concentration near the LSP and the TSP should be conducive to the flame kernel formation. This is mainly because of the fact that the above hydrogen distributions, not only lead to the rapid formation of the flame kernel near the LSP and the TSP, but also make use of the hydrogen at the early stage of combustion Stroke. Under the computational condition, the overall combustion rate for case A: 140 − 60 which had a HIT of 140°CA (BTDC) and a HIA of −60°CA, was the fastest. Compared with case C: 300 + 60 which had a HIT of 300°CA (BTDC) and a HIA of 60°CA, the peak pressure of case A: 140 − 60 was raised by 31.1%. However, compared with other cases, the NO emissions of case A: 140 − 60 at 80°CA (ATDC) was the maximum. Furthermore, for engineering applications, this study also provided a scheme of the change of the optimum HIA under different HITs for improving the performance of the HDI + NGPI rotary engine.

  • combined effect of injection timing and injection angle on mixture formation and combustion process in a direct injection di natural gas rotary engine
    Energy, 2017
    Co-Authors: Baowei Fan, Jianfeng Pan, Zhenhua Pan, Wenming Yang, Stephen Bani, Wei Chen
    Abstract:

    Abstract The application of direct injection (DI) technology is considered as a key solution to the problems of combustion efficiency and emissions on the rotary engine. This work aimed to numerically study the combined effect of injection timing (IT) and injection angle (IA) on mixture formation and combustion process in the 3D flow field of a DI natural gas rotary engine. On the basis of the 3D dynamic simulation model which was established in our previous work [29, 30], some critical information was obtained which was difficult to acquire through experiment. Simulation results showed that to satisfy the ideal fuel distribution for high combustion rate, a small IA should be used when the IT was at the early stages of Intake Stroke, and a big IA should be used when the IT was at the early stages of compression Stroke. However, when the IT was at the middle and later stages of Intake Stroke, the IA which could satisfy the ideal fuel distribution, was difficult to determine with the changed IT in the middle and later stage of Intake Stroke. For the above reason, the middle and late stage of Intake Stroke was not recommended as injection timing in engineering application.

  • experimental and numerical investigation of the fluid flow in a side ported rotary engine
    Energy Conversion and Management, 2015
    Co-Authors: Baowei Fan, Jianfeng Pan, Aikun Tang, Zhenhua Pan, Yuejin Zhu, Hong Xue
    Abstract:

    Abstract 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 600 rpm. 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.

Emhardt S - One of the best experts on this subject based on the ideXlab platform.

  • Preliminary explorations of the performance of a novel small scale opposed rotary piston engine
    'Elsevier BV', 2020
    Co-Authors: Gao J, Tian G, Jenner P, Burgess M, Emhardt S
    Abstract:

    With the increasing pressure of fossil fuel consumption and pollutions from vehicles powered by internal combustion engines, much attention has been attracted for hybrid and electric vehicles. With this background, an increasing demand for compact and high power density engines is being developed for the purpose of hybrid vehicles. In this paper, the design of a novel opposed rotary piston engine was investigated. In comparison with conventional reciprocating engines, this design has no crank connecting rods and Intake/exhaust valves, and the operation cycle takes 360° crank angle to complete but similar to a four Stroke cycle. 3D and 1D simulations were conducted to analyse the in-cylinder flow and evaluate the engine performance. The simulation results indicated the air velocity was very high at the end of Intake Stroke due to the lack of Intake valves. The opposed rotary piston engine had a higher fraction of constant volumetric combustion that yielded to less heat loss, which contributed to a higher power output per combustion cycle than a reciprocating engine at low engine speed. The estimated minimum brake specific fuel consumption and maximum power density were 240 g/(kW·h) and approximately 80 kW/L, respectively