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Jin-yuan Qian - One of the best experts on this subject based on the ideXlab platform.
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experimental and numerical analysis of Spring Stiffness on flow and valve core movement in pilot control globe valve
International Journal of Hydrogen Energy, 2017Co-Authors: Jin-yuan Qian, Jian Kai WangAbstract:Valves are widely used for fluid flow control, not only for conventional fluid like water, gas and oil, but also for hydrogen under high pressure and so forth. Under these new conditions, the response time and energy consumption of valves are closely related to the whole performance of the piping system. Pilot-control globe valve (PCGV) is a novel quick response valve, which can utilize the pressure difference before and after the valve core to control the open/close states of the main valve. In this paper, the effects of Spring Stiffness inside PCGV on the flow and the valve core movement are carried out, respectively. To begin with, the experimental setup is introduces and the 3D numerical model is established. The simulation is carried out in software FLUENT with RNG k-e turbulence model, User Defined Function method and dynamic mesh regeneration methods under transmit state. Then, a comparison of steady valve core displacements between experiment and simulation is carried out. After that, the effects of Spring Stiffness on flow characteristics, valve core movement and response times during opening and closing periods are presented. Finally, a Spring chosen correction equation is proposed. This work can benefit the further design work of PCGVs or similar valves with Springs, and it can be also referred by someone dealing with novel control valves design or flow control issues.
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transient simulation of valve core movement of pilot control globe valve in vertical pipelines
Paiguan Jixie Gongcheng Xuebao Journal of Drainage and Irrigation Machinery Engineering; 34(1) pp 51-65 (2016), 2016Co-Authors: Jin-yuan Qian, An Le LuAbstract:A novel pilot-control globe valve, which can be used in vertical pipelines with a lower driving energy consumption, is proposed. A governing equation for valve core motion is obtained through a theoretical analysis of the forces applied on the valve core. A 3D simulation of valve core motion is conducted in Fluent by using User Defined Function (UDF) to involve different Spring Stiffness, steady state displacements, impact speeds and transient state displacements. The results show that there are different opening modes for different Spring Stiffness. For smaller Spring Stiffness, the valve is subject to a quicker response to flow to ensure it can work properly; however, this can more easily result in a higher impact speed. With the increasing of Spring Stiffness, the steady displacement of the core reduces especially beyond a turning point. Besides, the numerical transient displacements with 0.9 and 1.1 times the Spring Stiffness show good agreement with those obtained from a theoretical analysis. It is found out that the real Spring design point should have 0.9 times the Spring Stiffness determined by the theoretical analysis. This paper provides a reference for designing and application of pilot-control globe valves or other valves with similar structures. (Less)
Jian Kai Wang - One of the best experts on this subject based on the ideXlab platform.
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experimental and numerical analysis of Spring Stiffness on flow and valve core movement in pilot control globe valve
International Journal of Hydrogen Energy, 2017Co-Authors: Jin-yuan Qian, Jian Kai WangAbstract:Valves are widely used for fluid flow control, not only for conventional fluid like water, gas and oil, but also for hydrogen under high pressure and so forth. Under these new conditions, the response time and energy consumption of valves are closely related to the whole performance of the piping system. Pilot-control globe valve (PCGV) is a novel quick response valve, which can utilize the pressure difference before and after the valve core to control the open/close states of the main valve. In this paper, the effects of Spring Stiffness inside PCGV on the flow and the valve core movement are carried out, respectively. To begin with, the experimental setup is introduces and the 3D numerical model is established. The simulation is carried out in software FLUENT with RNG k-e turbulence model, User Defined Function method and dynamic mesh regeneration methods under transmit state. Then, a comparison of steady valve core displacements between experiment and simulation is carried out. After that, the effects of Spring Stiffness on flow characteristics, valve core movement and response times during opening and closing periods are presented. Finally, a Spring chosen correction equation is proposed. This work can benefit the further design work of PCGVs or similar valves with Springs, and it can be also referred by someone dealing with novel control valves design or flow control issues.
Nguyen Ba Hung - One of the best experts on this subject based on the ideXlab platform.
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the effects of key parameters on the transition from si combustion to hcci combustion in a two stroke free piston linear engine
Applied Energy, 2015Co-Authors: Nguyen Ba Hung, Norimasa IidaAbstract:An investigation was conducted to examine the effects of key parameters such as intake temperature, equivalence ratio, engine load, intake pressure, spark timing and Spring Stiffness on the transition from SI combustion to HCCI combustion in a two-stroke free piston linear engine. Operation of the free piston engine was simulated based on the combination of three mathematical models including a dynamic model, a linear alternator model and a thermodynamic model. These mathematical models were combined and solved by a program written in Fortran. To validate the mathematical models, the simulation results were compared with experimental data in the SI mode. For the transition from SI combustion to HCCI combustion, the simulation results show that if the equivalence ratio is decreased, the intake temperature and engine load should be increased to get a successful SI-HCCI transition. However, the simulation results also show that the in-cylinder pressure is decreased, while the peak in-cylinder temperature in HCCI mode is increased significantly if the intake temperature is increased so much. Beside the successful SI-HCCI transition, the increase of intake pressure from Pin=1.1bar to Pin=1.6bar is one of solutions to reduce peak in-cylinder temperature in HCCI mode. However, the simulation results also indicate that if the intake pressure is increased so much (Pin=1.6bar), the engine knocking problem is occurred. Adjusting Spring Stiffness from k=2.9N/mm to k=14.7N/mm is also considered one of useful solutions for reducing the peak in-cylinder temperature in HCCI mode as well as avoiding engine knock. Besides, the change of spark timing is suggested as a benefic method to help the control of the SI-HCCI transition to be more convenient. To get a successful SI-HCCI transition with reducing of peak temperature in HCCI mode as well as avoiding engine knock, the simulation results show that the engine should be operated with following conditions: equivalence ratio ϕ=0.7, engine load RL=180Ω, intake temperature Tin=400K, intake pressure Pin=1.2bar, spark timing in SI mode xig=3mm and Spring Stiffness k=14.7N/mm.
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a study of a two stroke free piston linear engine using numerical analysis
Journal of Mechanical Science and Technology, 2014Co-Authors: Nguyen Ba HungAbstract:We studied a two-stroke free piston linear engine by numerical models and simulation. The numerical models consisted of three parts: dynamic model, linear alternator model, and thermodynamic model. These models were combined and solved by a program written in Fortran. To validate the numerical models, simulation results were compared with experimental data at the same initial conditions. To provide information for the study, the effects of key parameters such as equivalence ratio, reciprocating mass, spark timing, and Spring Stiffness on the operating characteristics as well as performance of the engine were investigated. The simulation results indicated that by using numerical models as mentioned, the calculation data were closely similar to experimental data. Besides, this engine showed a great benefit for dynamic of piston, electric power output, and performance as spark timing was adjusted near the cylinder head. By decreasing reciprocating mass and increasing Spring Stiffness, the piston dynamics as well as electric power output of the engine was also improved significantly. In addition, high engine performance could be easily obtained by optimizing the key parameters.
Norimasa Iida - One of the best experts on this subject based on the ideXlab platform.
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the effects of key parameters on the transition from si combustion to hcci combustion in a two stroke free piston linear engine
Applied Energy, 2015Co-Authors: Nguyen Ba Hung, Norimasa IidaAbstract:An investigation was conducted to examine the effects of key parameters such as intake temperature, equivalence ratio, engine load, intake pressure, spark timing and Spring Stiffness on the transition from SI combustion to HCCI combustion in a two-stroke free piston linear engine. Operation of the free piston engine was simulated based on the combination of three mathematical models including a dynamic model, a linear alternator model and a thermodynamic model. These mathematical models were combined and solved by a program written in Fortran. To validate the mathematical models, the simulation results were compared with experimental data in the SI mode. For the transition from SI combustion to HCCI combustion, the simulation results show that if the equivalence ratio is decreased, the intake temperature and engine load should be increased to get a successful SI-HCCI transition. However, the simulation results also show that the in-cylinder pressure is decreased, while the peak in-cylinder temperature in HCCI mode is increased significantly if the intake temperature is increased so much. Beside the successful SI-HCCI transition, the increase of intake pressure from Pin=1.1bar to Pin=1.6bar is one of solutions to reduce peak in-cylinder temperature in HCCI mode. However, the simulation results also indicate that if the intake pressure is increased so much (Pin=1.6bar), the engine knocking problem is occurred. Adjusting Spring Stiffness from k=2.9N/mm to k=14.7N/mm is also considered one of useful solutions for reducing the peak in-cylinder temperature in HCCI mode as well as avoiding engine knock. Besides, the change of spark timing is suggested as a benefic method to help the control of the SI-HCCI transition to be more convenient. To get a successful SI-HCCI transition with reducing of peak temperature in HCCI mode as well as avoiding engine knock, the simulation results show that the engine should be operated with following conditions: equivalence ratio ϕ=0.7, engine load RL=180Ω, intake temperature Tin=400K, intake pressure Pin=1.2bar, spark timing in SI mode xig=3mm and Spring Stiffness k=14.7N/mm.
S P Beeby - One of the best experts on this subject based on the ideXlab platform.
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a tunable kinetic energy harvester with dynamic over range protection
Smart Materials and Structures, 2010Co-Authors: I N Ayalagarcia, Dibin Zhu, M J Tudor, S P BeebyAbstract:This paper describes the development and implementation of a self-powered control system that autonomously adapts the resonant frequency of an electromagnetic vibration-based energy harvester to ambient vibration frequency. The tuning mechanism adjusts the harvester’s Spring Stiffness by varying the axial tensile force between two permanent magnets. The system adjusts the resonant frequency of the harvester from 64 to 78 Hz, increasing the operational bandwidth of the harvester from 0.26 to 14 Hz, using a single structure. The same tuning principle is also applied to protect the harvester from over range acceleration which could cause physical damage to its structure. The closed loop control uses the phase difference between the harvester output signal and ambient vibration, measured by an accelerometer attached to the vibration source, to adjust the tuning mechanism.