共查询到20条相似文献，搜索用时 15 毫秒
1.
The relationship between abrasive concentration, length of oscillating chamber, standoff distance and cutting depth, erosion rate as well as cutting specific energy was investigated by experiments in the submerge and surface conditions. The cutting and erosion capabilities of the pre-mixed abrasive water jet and the pulsed abrasive water jet were analyzed in contrast. It is shown that the maximum cutting depth and erosion rate of the pulsed abrasive water jet are respectively 1.67,1.72 and 1.39, 1.47 than the pre-mixed abrasive water jet in submerge and surface conditions. These results attained from the research are useful to increase the cutting efficiency, decrease the energy ratio and expand the application domains of the abrasive water jet. 相似文献
2.
Aiming at the status quote of long time for methane extraction and slow speed for laneway excavating in coal seams of Liziya south 2JHJ well, abrasive water jet slotting technology is adopted to improve the methane desorption and increase excavating speed in semi-coal laneway. Through analyzing damage model and protection against outburst mechanism, the process of Coal-Rock Mass being cut and fractured is studied. Through lab test on abrasive water jet cutting coal-bed gangue, a new abrasive water jet cutting device is successfully designed and made and all parameters are determined. It is showed that abrasive water jet can cut through a coal-bed gangue with thickness 60~80 mm and uniaxial compressive strength 62 MPa. After cutting coal seams by abrasive water jet, the surface area for methane is enlarged and then coal seams pressure fell rapidly. Therefore the permeability and desorption of coal seams are greatly increased. The results are as follows: the average productivity of single-hole was enhanced by 2.83 times. 相似文献
3.
Liang Xichang 《保鲜与加工》1989,(1):1-7
The paper describes a new theory and methods for designing hyperbola, degenerate circles, involute and roulette curves which have been applied in grinding convex involute gears, cutting special profiles on a gear shaper, grinding the race-way of ball thrust bearings, form grinding and grinding cyclo-cycloidal gears with an abrasive belt. All these applications have been used in industruy with considerable benefits.
The curves are produced by different combinations of straight line and circle motions, Given the curve parameters of the workpieces to be machined, the best approximate curve can be obtained from a computer program designed for this purpose. 相似文献
4.
Abrasive water jets can incise objects with strong rigidity under water. The analytical means of kinetic theory is optimal for theoretical problems of submerged abrasive water jets. The flow characteristics in submerged abrasive water jets were analyzed based on kinetic theory for multiphase flows. The impact characteristics of every phase in submerged abrasive water jets was analyzed and continuity and momentum equations subsequently were developed for solid, gas and liquids in submerged abrasive water jets. It is shown that if the distributing function of every phase were given, the law of its movement could be ascertained. 相似文献
5.
前混合磨料射流超强的打击力主要是由高速磨料群提供的,因此,磨料速度测试是磨料打击力分布规律等研究的基础。针对传统研究方法的不足之处,笔者提出采用PIV技术结合自主编程设计的磨料中心识别程序,实现非接触式测试手段下磨料速度测试实验研究,并利用该方法简要分析了喷嘴结构对磨料速度的影响。结果表明,在一定范围内增加直线段长度有利于提高喷嘴出口处磨料的速度,表明在喷嘴直线段末端磨料依然处于明显的加速状态;增加收敛段长度对提高喷嘴出口处磨料速度有一定的作用,但磨料速度增幅不大;收敛角较大时,液相在收敛段前半段加速缓慢而在后半段过于剧烈,因磨料颗粒加速滞后于液相的原因导致喷嘴出口处磨料速度降低。 相似文献
6.
Experimental analysis of abrasive belt grinding of glass fiber reinforced plastic composite material
Abrasive belt grinding experiments of glass fiber reinforced plastics composite material are carried out by using three different abrasive belts with different sizes,and the interaction principle between the abrasive and the workpiece is analyzed.The main factors of material removal rate and belt life of glass fiber reinforced plastics composite material are obtained through a large number of tests and test data.The extent and the main reason of belt plug are analyzed through the professional image analysis software (Image Pro Plus) for the first time.The results show that in the process of abrasive belt grinding,the material removal rate are affected by the factors for grinding pressure,belt speed,abrasive type and size,and the ceramic abrasive belt has the highest removal rate.The main factor for belt plug extent is grinding pressure.The most important wear form of abrasive belt is blunt,and the accumulation abrasive belt has the longest life,followed by ceramic abrasive belt. 相似文献
7.
Zeng Zhong 《保鲜与加工》1992,(3):6-10
There are three actions of different features exerted upon the work surface by the abrasive grains on the working surface of the wheel during grinding process: they are elastic scratching, plastic pressing and cutting. The heat transformed by these three actions as well as the rubbing between the wheel bond and the work surface contributes to the integrated average temperature on the contact zone between the wheel and the work. In this paper the measurement and calculation of this integrated average temperature and the temperature distribution in the work are given, the influences of various grinding parameters are also studied. 相似文献
8.
Experimental analysis of the abrasive belt follow-up grinding of Zirconium-4 alloys tubes and pipes 总被引：1，自引：1，他引：0
Abrasive belt grinding experiments of Zr-4 nuclear power tube are carried out by using three different abrasive belts with same size, and the interactive generating mechanism between abrasive and workpiece is analyzed, the main factors of material removal rate and surface roughness of Zr-4 alloys are obtained. With the help of the advanced test facilities, the abrasive grain abrasion and surface topography of the workpiece are observed. The metallographic structure and microhardness of the layer of burnt surface during Zr-4 alloys Grinding are analyzed. Some conclusions are given as follows: the material removal rate and surface roughness are mainly affected by the factors of belt speed, grinding pressure, hardness of the contact wheel and abrasive type, of which, the belt speed is the strongest factor. The adhesion wear of the Zirconium corundum and aluminium oxide abrasive grit is more serious, the most important wear form of silicon carbide is abrasion wear. With the onset of grinding burn, the mechanical properties of Zr-4 alloys are deteriorated obviously. The results provide a theoretical and experimental basis for technical optimization in the grinding of Zr-4 alloys with efficiency and high quality. 相似文献
9.
This paper theoretically investigates the characteristics of cavitating bubbles in the pulsed abrasive water jet(PAWJ) and establishes the dynamic equations of cavitating bubbles. The effects of abrasive diameter and density on the spherical bubble collapse are also analyzed. It is found that the change of abrasive diameter rarely affects the bubble collapse when the abrasive diameter and density are small whereas the smaller abrasive greatly blocks the bubble collapse when the abrasive diameter and density are comparably big. It is also shown that when the abrasive density is increased, the fluid viscosity rises, and the kinetic energy of the abrasives near the collapsed bubble is enhanced and meanwhile the intensity of cavitating erosion is weakened. 相似文献
10.
The effects of cavitation and abrasive acceleration in the self excited oscillation pulsed abrasive water jets are directly determined by its oscillating frequencies, so the wave speed in the jets and its effects on pulsed frequencies are discussed. The numerical results show that the oscillating frequencies of the jets increase obviously with decreasing wave speed, and the abrasive parameters have almost no effects on the wave speed, whereas the exit of air in fluid has significant consequences on the wave speed.It was found that these conclusions were applicable for design the nozzle of the jets. 相似文献
11.
The stainless steel has excellent properties, but it is difficult-to-grind material. Because belt grinding shows many advantages, grinding experiments with four kinds of abrasive grain on stainless steel are carried out. The correlation mechanism between the abrasive grits and the workpiece, and influence factors on material removal rate are discussed. A scanning electric microscope was used to investigate the surface micro-shape characteristics of abrasive grit and workface. The material removal mechanism and the wearing types of abrasive belt are also analyzed. 相似文献
12.
沙生柽柳扦插苗生根条件优化研究 总被引：2，自引：1，他引：1
针对流沙固定先锋树种沙生柽柳扦插苗不易生根的问题,进行了沙生柽柳扦插基质、插穗长度、插穗木质化程度及外源激素处理等关键因素筛选试验,探讨沙生柽柳扦插繁殖优化条件。结果表明：沙生柽柳扦插繁殖能力普遍较低,插穗成活率在6.67%~31.11%之间;插穗选用15cm长的1年生硬枝为宜,1年生硬枝扦插成活率高达31.11%,15cm插穗成活率为10.37%;扦插基质以保湿性能较好的壤土为宜,插穗成活率9.63%;外源激素诱导以200mg/L的IBA浸泡20min效果最佳,不同激素类型诱导中,IBA处理效果最好,插穗最高成活率达14.07%,为CK对照处理的6~7倍;不同激素浓度诱导中,200mg/L低浓度IBA处理插穗成活率高达22.22%;不同激素处理时间诱导中,经20min浸泡的IBA激素处理的插穗成活率24.44%。 相似文献
13.
对百香果进行扦插试验研究,明确影响百香果扦插效果的关键因素,优化扦插处理的最佳组合,为百香果的快速繁殖提供技术支持。采用3因素3水平正交试验设计,研究分析插穗茎段部位、NAA浓度、扦插基质3个因素对百香果扦插效果的影响,并采用排队评分和公式评分法对扦插成活效果进行综合分析,筛选优化出百香果扦插繁殖的最佳处理组合。插穗部位对百香果扦插成活率的影响最大,NAA浓度和扦插基质的影响相对较小。对根数、平均根粗的影响由大到小为插穗部位、扦插基质、NAA浓度,对平均根长、新生蔓长、新生叶片数的影响由大到小为插穗部位、NAA浓度、扦插基质。综合评分结果表明,插穗部位是影响百香果扦插效果的最主要因素,其次为扦插基质,而NAA浓度的影响最小。百香果扦插的最佳组合为A2B3C3处理,即以中部半木质化茎段为插穗,用300 mg/L的NAA溶液浸泡20 min,选用泥炭混合基质（泥炭:黄壤=1:1）为扦插基质时,百香果的扦插效果最为理想。 相似文献
14.
A mono-liquid model is established according to formative character of the premixed abrasive water jet. The hydraulic structure is analyzed by the model. The relationship that is obtained between the axial shaft line velocity and the forget distance by the law of conservation of momentum is verified with the experiment. 相似文献
15.
为了探讨天津地区饲用小黑麦最佳收获模式,在小黑麦返青后采用裂区试验设计,对不同刈割时期和留茬高度下小黑麦的生物产量和营养成分进行测定,结果表明:随着留茬高度的增加,小黑麦年总干物质产量、干物质含量以及干物质中中性洗涤纤维和酸性洗涤纤维含量呈下降趋势,干物质中粗蛋白、总糖、可溶性糖和淀粉含量则呈上升趋势;随着刈割时期的延长,小黑麦干物质含量、干物质中中性洗涤纤维、酸性洗涤纤维、总糖和淀粉含量呈增加趋势,年总干物质产量和可溶性糖含量呈先增(乳熟中期最高)后减的趋势,而粗蛋白含量呈下降趋势;根据隶属函数法对小黑麦的综合利用方式进行评价,优选乳熟中期10.0 cm刈割制作青贮,其次为拔节期10.0 cm刈割制作优质小黑麦干草或青饲。 相似文献
16.
切削液的合理选择是提高切削加工绿色化程度的重要途径之一。根据绿色制造原理,在首先满足加工质量的前提下,建立了一种综合考虑时间、质量、成本、资源消耗和环境影响5个因素的切削液评价体系。采用油基切削液和不同类型的水基切削液进行剃齿加工对比试验,从工件质量、刀具寿命、成本和资源环境影响几个方面进行对比分析。结合试验结果,利用模糊综合评价方法对加工结果进行了评价,并据此提出了用于剃齿加工的切削液综合选择模型,通过剃齿加工实例验证了该模型的可行性。试验证明：采用水基切削液进行剃齿加工仍能满足质量要求,与传统油基切削液相比,水基能有效降低生产成本,同时减少对环境的污染。 相似文献
17.
断根、环割对烟草体内钾、钙、镁循环和积累的影响 总被引：3，自引：1，他引：2
在网室内采用水培方式栽培烟草,于烟草打顶期及打顶后一周进行断根、环割处理,探讨断根、环割及断根+环割对烟草吸收钾、钙、镁和烟株体内钾、钙、镁循环、积累的影响。结果表明：断根降低了木质部汁液单位时间的钙、镁吸收循环量及钙、镁在韧皮部的积累量,而环割处理的结论刚好相反。断根+环割显著提高了木质部汁液单位时间的钾吸收循环量和烟叶的钾积累量,提高上部叶的钾含量,降低了中、下部烟叶钙、镁的含量,因此该处理提高烟叶品质的效果最好。 相似文献
18.
[目的]旨在提出合理地间伐模式提高杨-油菜复合经营的效益。[方法]以长江流域滩地杨-油菜复合模式为研究对象,针对3年树龄的杨树进行间伐处理,各处理类型分别为：砍小留大、隔2伐1及隔1伐1。通过不同间伐处理下林内小气候因子、油菜产量及品质等的测定,初步研究了间伐处理对杨-油菜复合模式的影响。[结果]结果表明,对照样地空气及土壤温度较低、湿度较大,而隔1伐1样地空气及土壤温度较高、湿度较小,光合有效辐射最大。通过间伐处理的3种样地内油菜性状要好于对照样地。其中,隔2伐1样地内油菜籽含水率最低为12.89%且产量高达215.48 g.m-2,同时油菜籽脂肪含量最高为35.9%。[结论]说明隔2伐1这种间伐模式表现最好。通径分析表明,小气候对油菜产量及品质均产生了直接或间接影响。 相似文献
19.
不同基质对山茶花扦插生长的影响 总被引：4，自引：2，他引：2
为研究不同扦插基质对山茶花扦插生长的影响,选择4种不同基质：S1（河沙）、基质S2（黄心土）、基质S3（黄心土∶河沙=1∶1）、基质S4（黄心土∶河沙=2∶1）对山茶花进行对比扦插试验。结果表明：4种不同基质的扦插苗生根率、苗高、新梢长之间存在着极显著差异。基质S4对扦插苗生根效果最好,扦插苗鲜重与根系生物量最大,平均总鲜重达到2.41 g/株;基质S2对扦插苗生长最佳,地上干重最大,平均达到0.95 g/株。因此,茶花扦插育苗的适宜基质为S4,其次为基质S2,建议在生产上推广应用。 相似文献
20.
海南黎药裸花紫株扦插育苗技术研究 总被引：2，自引：1，他引：1
为了建立高效的裸花紫株扦插育苗技术体系,从插穗年龄、粗度、生根药物处理等方面对裸花紫珠扦插育苗技术进行研究。结果表明：以2年生插穗的生根率最高,为38.6%,直径0.6~0.8 cm的插穗其生根率最高,为53.6%,所用生根粉均能显著提高生根率,其中以ABT7号生根粉效果最好,生根率最高为94.6%。插条年龄和插穗粗度对裸花紫株扦插生根率有显著影响,其中以直径0.6~0.8 cm 2年生插穗的生根率最高;ABT6、ABT7和ABD生根粉对裸花紫珠扦插生根均有明显的促进作用,其中以ABT7的生根效果最好。 相似文献