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用一台Ricardo E6可变压缩比单缸试验机研究了二氧化碳含量的变化对生物质气发动机动力性,经济性及排放指标的影响。结果表明,随着二氧化碳含量的增加,发动机的功率及热效率均有所下降,上述性能指标的降低可通过提高压缩比来改善,虽然二氧化碳的存在几乎不影响CO排放,略微增加了HC,但显著地降低了排气中NOx含量。 相似文献
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汽油机进行排气再循环时的参数优化试验研究 总被引:2,自引:0,他引:2
在EQ6100汽油机上进行的大量试验表明,各种负荷工况下排气再循环都能显著降低 NOX排放,但HC 和CO排放及油耗率随EGR率的变化关系则较为复杂,各工况下在下一个最优EGR率。试验结果还表明,进行EGR时的燃空当量比和点火提前角等参数也需要进行相应的调整和优化。这些措施为设计实用的EGR系统提供了依据。 相似文献
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在缸内直喷汽油机(GDI)上采用多次燃油喷射和可变配气技术来控制缸内混合气形成和燃烧,实现了SI/HCCI复合燃烧方式。研究了不同压缩比和辛烷值对均质混合气压燃(HCCI)燃烧排放特性的影响。结果表明,汽油HCCI燃烧呈现单阶段燃烧燃料特性,HCCI着火发生在上止点附近时油耗低。低压缩比下,HCCI燃烧可以在较浓空燃比下工作,NOx排放较高。高辛烷值燃料HCCI燃烧可运行的负荷范围窄。汽油HCCI发动机在偏高压缩比条件下燃用偏低辛烷值汽油可以获得较好的经济性和排放性能。 相似文献
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高能(电子)点火系与供油系匹配试验研究 总被引:5,自引:1,他引:4
通过对两种点火系进行定功率质量调整对比,说明高能点火可燃用较少的汽油而发生同样的功率,因而排放与油耗率均得到改善,据此试验结果,对化油器进行匹配调整,取得提高发协机动力性(Pe max提高3.9%),改善经济性和降低排放(常用工况油耗率下降4.7%,CO和HC平均下降50%以上)的效果,动态性能也有明显提高。试验还表明,高能点火正确匹配使用,它不但是机内净化的有效装置,也是改善发动机性能的重要途径 相似文献
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《内燃机与动力装置》2015,(3):29-33
本文将生物质燃气作为分布式供能系统内燃机的替代燃料,并利用GT-Power软件对该种内燃机进行性能模拟和动力性优化,以达到节能减排的目的。模拟结果显示,生物质气的燃烧压力较低,使得生物质气内燃机的有效功率偏低,中速时仅为天然气内燃机的1/3。在1500r/min固定转速下,优化压缩比、点火提前角和空燃比等参数的取值能够有效提高生物质气内燃机的动力性,同时改善燃料消耗和排放性。因此多参数优化的方法可以提高生物质气内燃机的综合性能,使其满足分布式供能系统的特殊要求。 相似文献
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LPG-汽油双燃料发动机试验研究 总被引:9,自引:0,他引:9
选用澳华液化石油气(LPG)有限公司生产的汽车用石油气燃料供给管理配于EQ6100-I型发动机,改装成LPG-汽油双燃料发动机,进行性能测试分析。试验结果表明,在不改变原机压缩比和点火提前角时,燃用液化石油气的动力性下降,最大功率为原机的90%;最大扭矩为原机的92%。燃用LPG比燃用汽油的当量比油耗低,节能率在5%左右。怠速排放试验表明,燃用LPG的CO,HC排放浓度分别为燃用贩50%和36%。 相似文献
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甲醇燃料在车用发动机上的应用研究 总被引:10,自引:1,他引:9
结合甲醇燃料的理化特性,分别在495Q和JT468Q汽油发动机进行了燃用高比例M85甲醇汽油燃料和全甲醇燃料的对比试验。试验结果表明:直接燃烧定比例甲醇燃料时,功率和扭矩都略有提高;提高压缩比后,功率和扭矩都大幅度提高,燃油消耗也大幅度降低、排放明显改善。 相似文献
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Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden. 相似文献
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《热能动力工程》2014,(5)
正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%. 相似文献
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The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°, −5°, +5°, +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods. 相似文献
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A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified. 相似文献
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As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied. 相似文献
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The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σred = σ1 β + (1 − β)σi, where: σ1-maximal principal stress, σi-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures. 相似文献
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Jaime Massanet-Nicolau Alan Guwy Richard Dinsdale Giuliano Premier Sandra Esteves 《International Journal of Hydrogen Energy》2010
Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H2 kg−1 VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min−1 successfully prevented a decline in hydrogen production and resulted in a yield of 27.0 L H2 kg−1 VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production. 相似文献