Experiments and Modelling of Producer Gas Based Reciprocating Engines

2002 ◽  
Author(s):  
G. Sridhar ◽  
P. J. Paul ◽  
H. S. Mukunda
Keyword(s):  
Flame Propagation ◽  
Three Dimensional ◽  
Line Emission ◽  
Performance Testing ◽  
Propagation Speed ◽  
Producer Gas ◽  
Transient Effects ◽  
Ignition Timing ◽  
Piston Bowl ◽  
On Line

A 20 kW reciprocating engine is operated using producer gas derived from a modern open top downdraft re-burn biomass gasifier that has been evaluated by rigorous laboratory performance testing over several hundred hours. The engine is operated at varying compression ratio (CR) from 11.5 to 17.0 and ignition timings from 30 to 6° before Top Centre (TC). The engine – alternator system is characterised for its performance by the simultaneous measurement of gas and airflow rates, gas composition (on-line), emission levels and power delivered. It is also instrumented to obtain the in-cylinder behaviour in the form of pressure-crank angle (p – θ) diagram to assess the thermodynamic behaviour of the engine. Three-dimensional (3-D) simulation of the flow field in the combustion chamber (involving piston-bowl arrangement) through the cycle up to the start of the combustion is used to obtain inputs on the turbulence intensity (u′) and length scale (lT) for the modelling of the flame propagation process in a zero-dimensional model (0-D) designed to predict the p – θ curve. The flame propagation and heat release processes make use of eddy entrainment and laminar burn-up model. The data on u′ extracted from the 3-D flow calculations match reasonably well with experiments till compression stroke but are in contradiction with trends close to TC. This is reasoned to be due to limitation of the k-ε model to capture transient effects due to reverse squish phenomenon. The 0-D model took into account the experimental behaviour of the u′ in the post-TC period to attempt to match the observed p – θ data over a range of CRs and ignition timing advances. While these predictions match well with the experimental data at advanced ignition timing at both higher and lower CRs, the peak pressure is under-predicted at lower ignition advances; reason are traced to increase in flame area and propagation speed due to reverse squish effect. When these are accounted in the model, the p – θ curves are predicted better.

Effect of Different Ignition Methods on Combustion Characteristics of a Turbocharging Lean Burn LPG Engine

2012 ◽  
Vol 443-444 ◽  
pp. 1026-1031
Author(s):  
Da Wei Qu ◽  
Jun Li ◽  
Ying Gao ◽  
Dong Qing Zhou ◽  
Lu Yan Fan ◽  
...  
Keyword(s):  
Flame Propagation ◽  
Three Dimensional ◽  
Propagation Speed ◽  
Propagation Distance ◽  
Spark Ignition ◽  
Simulation Software ◽  
Combustion Model ◽  
Power Performance ◽  
Working Process ◽  
Lean Burn

A turbocharging lean burn LPG engine combustion model is set up by using three-dimensional simulation software. And the numerical simulation of the engine working process is done. Based on the model validation, the effect of the engine working process is calculated and analyzed by comparing with different ignition models (single spark ignition and dual spark ignition) and the simulation results are validated by experiments. The results show that: dual spark ignition (DSI) model as compared to single spark ignition (SSI) model can reduce flame propagation distance, form the stronger swirl rapidly, accelerate the flame propagation speed, reduce knock phenomena, reduce the emission temperature and improve the engine efficiency. Therefore, the engine has better power performance and fuel economy.

Research on LPG Dual-Spark Ignition Engine Combustion by CFD

2012 ◽  
Vol 443-444 ◽  
pp. 1032-1038 ◽  
Author(s):  
Dong Qing Zhou ◽  
Jun Li ◽  
Ying Gao ◽  
Da Wei Qu ◽  
Qi Jie Liu
Keyword(s):  
Flame Propagation ◽  
Three Dimensional ◽  
Propagation Speed ◽  
Propagation Distance ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Lean Burn ◽  
Dimensional Simulation ◽  
Model Engine ◽  
Combustion Optimization

.To study the dual-spark ignition methods of combustion of LPG, numerical simulation is conducted on the lean burn LPG turbocharged engine by three-dimensional simulation software.Based on the model validation test of dual-spark ignition model engine, the effect of synchronization ignition and asynchronous ignition are discussed.The results obtained show that asynchronous dual spark ignition model can be helpful to reduce flame propagation distance, form the stronger swirl rapidly,accelerate the flame propagation speed significantly,improve the rapid lean-burning process of LPG engine. Meanwhile, the results will also offer theoretical guidance for combustion optimization.

Design and calibration of an IVEM for general 3-dimensional imaging of non-diffracting materials

1992 ◽  
Vol 50 (2) ◽  
pp. 1040-1041
Author(s):  
Neil Rowlands ◽  
Jeff Price ◽  
Michael Kersker ◽  
Seichi Suzuki ◽  
Steve Young ◽  
...  
Keyword(s):  
3D Imaging ◽  
Tomographic Reconstruction ◽  
Three Dimensional ◽  
3 Dimensional ◽  
3D Microstructure ◽  
Image Translation ◽  
Digital Correlation ◽  
On Line ◽  
Mechanical Stage ◽  
Projection Angle

Three-dimensional (3D) microstructure visualization on the electron microscope requires that the sample be tilted to different positions to collect a series of projections. This tilting should be performed rapidly for on-line stereo viewing and precisely for off-line tomographic reconstruction. Usually a projection series is collected using mechanical stage tilt alone. The stereo pairs must be viewed off-line and the 60 to 120 tomographic projections must be aligned with fiduciary markers or digital correlation methods. The delay in viewing stereo pairs and the alignment problems in tomographic reconstruction could be eliminated or improved by tilting the beam if such tilt could be accomplished without image translation.A microscope capable of beam tilt with simultaneous image shift to eliminate tilt-induced translation has been investigated for 3D imaging of thick (1 μm) biologic specimens. By tilting the beam above and through the specimen and bringing it back below the specimen, a brightfield image with a projection angle corresponding to the beam tilt angle can be recorded (Fig. 1a).

Digitalization system of ancient architecture decoration art based on neural network and image features

2020 ◽  
pp. 1-12
Author(s):  
Wu Xin ◽  
Qiu Daping
Keyword(s):  
Neural Network ◽  
Construction Industry ◽  
Three Dimensional ◽  
Performance Testing ◽  
Image Features ◽  
Three Dimensional Model ◽  
Performance Effect ◽  
Data Process ◽  
And Performance ◽  
Construction Mode

The inheritance and innovation of ancient architecture decoration art is an important way for the development of the construction industry. The data process of traditional ancient architecture decoration art is relatively backward, which leads to the obvious distortion of the digitalization of ancient architecture decoration art. In order to improve the digital effect of ancient architecture decoration art, based on neural network, this paper combines the image features to construct a neural network-based ancient architecture decoration art data system model, and graphically expresses the static construction mode and dynamic construction process of the architecture group. Based on this, three-dimensional model reconstruction and scene simulation experiments of architecture groups are realized. In order to verify the performance effect of the system proposed in this paper, it is verified through simulation and performance testing, and data visualization is performed through statistical methods. The result of the study shows that the digitalization effect of the ancient architecture decoration art proposed in this paper is good.

Experimental and simulation study of impurity transport response to RMPs in RF-heated H-mode plasmas at EAST

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Germán Vogel ◽  
Hongming Zhang ◽  
Yongcai Shen ◽  
Shuyu Dai ◽  
Youwen Sun ◽  
...  
Keyword(s):  
Inner Core ◽  
Extreme Ultraviolet ◽  
Transport Coefficients ◽  
Three Dimensional ◽  
Line Emission ◽  
Core Region ◽  
Emission Mitigation ◽  
One Dimensional ◽  
Impurity Transport ◽  
Transport Code

Spatial profiles of impurity emission measurements in the extreme ultraviolet (EUV) spectroscopic range in radiofrequency (RF)-heated discharges are combined with one-dimensional and three-dimensional transport simulations to study the effects of resonant magnetic perturbations (RMPs) on core impurity accumulation at EAST. The amount of impurity line emission mitigation by RMPs appears to be correlated with the ion Z for lithium, carbon, iron and tungsten monitored, i.e. stronger suppression of accumulation for heavier ions. The targeted effect on the most detrimental high-Z impurities suggests a possible advantage using RMPs for impurity control. Profiles of transport coefficients are calculated with the STRAHL one-dimensional impurity transport code, keeping $\nu /D$ fixed and using the measured spatial profiles of $\textrm{F}{\textrm{e}^{20 + }}$ , $\textrm{F}{\textrm{e}^{21 + }}$ and $\textrm{F}{\textrm{e}^{22 + }}$ to disentangle the transport coefficients. The iron diffusion coefficient ${D_{\textrm{Fe}}}$ increases from $1.0- 2.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ to $1.5- 3.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ from the core region to the edge region $(\rho \gt 0.5)$ after the onset of RMPs. Meanwhile, an inward pinch of iron convective velocity ${\nu _{\textrm{Fe}}}$ decreases in magnitude in the inner core region and increases significantly in the outer confined region, simultaneously contributing to preserving centrally peaked $\textrm{Fe}$ profiles and exhausting the impurities. The ${D_{\textrm{Fe}}}$ and ${\nu _{\textrm{Fe}}}$ variations lead to reduced impurity contents in the plasma. The three-dimensional edge impurity transport code EMC3-EIRENE was also applied for a case of RMP-mitigated high-Z accumulation at EAST and compared to that of low-Z carbon. The exhaust of ${\textrm{C}^{6 + }}$ toward the scrape-off layer accompanying an overall suppression of heavier ${\textrm{W}^{30 + }}$ is observed when using RMPs.

scholarly journals Three-dimensional platinum nanoparticle-based bridges for ammonia gas sensing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nishchay A. Isaac ◽  
Johannes Reiprich ◽  
Leslie Schlag ◽  
Pedro H. O. Moreira ◽  
Mostafa Baloochi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Response Times ◽  
High Surface ◽  
Three Dimensional ◽  
Performance Testing ◽  
Volume Ratio ◽  
Platinum Nanoparticle ◽  
Ammonia Gas ◽  
Lift Off

AbstractThis study demonstrates the fabrication of self-aligning three-dimensional (3D) platinum bridges for ammonia gas sensing using gas-phase electrodeposition. This deposition scheme can guide charged nanoparticles to predetermined locations on a surface with sub-micrometer resolution. A shutter-free deposition is possible, preventing the use of additional steps for lift-off and improving material yield. This method uses a spark discharge-based platinum nanoparticle source in combination with sequentially biased surface electrodes and charged photoresist patterns on a glass substrate. In this way, the parallel growth of multiple sensing nodes, in this case 3D self-aligning nanoparticle-based bridges, is accomplished. An array containing 360 locally grown bridges made out of 5 nm platinum nanoparticles is fabricated. The high surface-to-volume ratio of the 3D bridge morphology enables fast response and room temperature operated sensing capabilities. The bridges are preconditioned for ~ 24 h in nitrogen gas before being used for performance testing, ensuring drift-free sensor performance. In this study, platinum bridges are demonstrated to detect ammonia (NH3) with concentrations between 1400 and 100 ppm. The sensing mechanism, response times, cross-sensitivity, selectivity, and sensor stability are discussed. The device showed a sensor response of ~ 4% at 100 ppm NH3 with a 70% response time of 8 min at room temperature.

scholarly journals Performance testing of a downdraft biomass gasifier stove for cooking applications

2018 ◽  
Vol 204 ◽  
pp. 04011
Author(s):  
Woranuch Jangsawang
Keyword(s):  
Primary School ◽  
Thermal Efficiency ◽  
Fixed Bed ◽  
Performance Testing ◽  
Rural School ◽  
High Potential ◽  
Producer Gas ◽  
Biomass Fuels ◽  
Heating Value ◽  
Gas System

A down draft biomass gasifier stove with four steps of cleaning gas system was developed to produce the producer gas for replacing LPG for cooking applications in lunch project for the student in rural school area. This project has been implemented at Bangrakam primary school that located at Pitsanuloke Province, Thailand. The biomass fuels used are Mimosa wood twigs. The gasifier stove was developed based on down draft fixed bed gasifier with the maximum fuel capacity of fourteen kilograms. The performance testing of the biomass gasifier stove showed that the heating value of the producer gas is 4.12 MJ/Nm3 with the thermal efficiency in the percentage of 85.49. The results from this study imply that it has high potential to replace LPG with producer gas.

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