共查询到20条相似文献,搜索用时 78 毫秒
1.
2.
在进行巷道贯通时,需要对2个巷道的点位进行准确测量.研究了腾晖-海圣联合开采时主副运输巷的贯通测量工作,主要包括地面控制测量、联系测量和井下陀螺全站仪定向测量、井下导线测量和高程测量,可以为巷道的贯通测量提供一定的参考. 相似文献
3.
现代测量技术在煤矿测量中的应用具有重要性与必要性。叙述并分析了全站仪、全球定位系统、三维激光技术、惯性测量系统以及遥感测量技术等现代测量技术在煤矿测量中的应用。 相似文献
4.
在生产与试验中,正弦波交流电信号通过非线性负载后波形会发生畸变。对于此类非正弦波交流电有效值的测量,使用普通的测量仪表测量会导致较大的测量误差。为使测量不受波形影响,普通的测量仪表已经不能满足测量要求,在越来越多的场合需要使用真有效值测量设备进行测量。本研究结合发电机组试验设备在实践中出现的问题,对真有效值的测量应用进行了分析和研究。 相似文献
5.
6.
7.
通过对目前常用的中高压电网电能质量测量互感器工作特性的分析,结合电能质量参数指标,指出了每种互感器在电能质量测量中存在的问题,根据其频率特性给出了正确应用范围。针对互感器在测量中存在的因中性点不直接接地导致的谐波测量失真问题,给出了解决办法;对只适合基频测量的电容式电压互感器设计了测量电路,使其可用来进行宽频带信号测量;最后给出了不同电网电能质量参数测量所适用的互感器,保证测量结果的准确性。 相似文献
8.
GPS-RTK测量技术目前在各海测大队还处于试验探索阶段,但其测量模式和测量速度、精度比较以往的测量方式有了很大的优势,RTK测量技术的普及势在必行,笔者结合实际工作体会就其在测量工作应用的优劣作简要分析,并提出解决方案。 相似文献
9.
10.
11.
通过对发动机气道内气体流动过程的相似分析,在雷诺Re准则数足够大的前提下,非定性准则欧拉Eu数和相似不变量无因次涡流NR保持不变。这就证实通过稳流试验来测量气道的流通性能是可行的。通过数理推导,评价参数流量系数μσ真实就是欧拉Eu准则数的一种表现形式。 相似文献
12.
13.
14.
15.
为研究锥阀空化现象,运用ANSYS Fluent流体力学有限元计算软件,分析锥阀在内流和外流两种情形下的流场,得到锥阀在内流和外流两种流动方式下空化区域0~3s内气体的体积分数。计算对比发现,在液体流速和压力的突变区域空化现象明显,外流较内流空化区域大,空化程度比内流严重。为降低空化现象对锥阀型腔造成的损伤,优化锥阀型腔阀芯结构,优化模型1可避免内流时空化的发生,优化模型2在内流和外流情况下均能有效避免空化的发生,优化模型2的结构形式更为合理。研究成果可为锥阀设计提供参考。 相似文献
16.
An experimental study on the shape of a single bubble similar to those observed in a horizontal plug/slug flow was performed using visual observation and conductance probes. The results indicated that the shapes of the bubble nose and the bubble body depend on the Froude number defined by gas/liquid mixture velocity, whereas the shape of the back region of the bubble depends on both the Froude number and bubble length. The photographic images showed that the structural feature of the bubble head is related to the motion characteristics of the bubble. The transition from plug flow to slug flow occurs when the tail of the bubble changes from a staircase to hydraulic jump pattern with the increasing of the Froude number and bubble length. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(5): 276– 285, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20161 相似文献
17.
Experimental Studies on The Mechanism and Control of Secondary Flow Losses in Turbine Cascades 总被引:2,自引:0,他引:2
This paper summarizes the results of the authors' 4 year experimental studies on the secondary flow losses in turbine cascades. Cascade wind tunnel experiments were carried out concerning the influence of aspect ratios, incidence, turning angles and outer endwall divergent angles in order to unveil the evolution mechanism of secondary flow losses in turbine cascades without end clearance. Some methods for controlling the secondary flows are investigated including the blade leaning, blade cambering, endwall convergence and leading edge extension at two ends of the blade. 相似文献
18.
Bo LIU Weimin HOU Changyou MA Yangang WANG Qiang ZHOU 《Frontiers of Energy and Power Engineering in China》2008,2(4):448-452
The dynamic pressure measurement device and test technology are described in this study. The tip clearance unsteady flow development
from the inlet to the outlet of an axial-flow rotor was revealed by analyzing pressure frequency spectrum acquired from measuring
the unsteady pressure field of the tip endwall. The experiment provides test basis for thoroughly understanding the tip clearance
unsteady flow and building interaction models of tip clearance flow and main flow.
__________
Translated from Compressor, Blower & Fan Technology, 2007, (5): 12–15 [译自: 风机技术] 相似文献
19.
Yiping Liu Weilin Yang Jing Wang 《Frontiers of Energy and Power Engineering in China》2008,2(2):152-157
Theoretical relations that predict the transition from a stratified pattern to a slug pattern, including a onedimensional
wave model that contains less empiricism than the commonly used Taitel-Dukler model, and the ideal model for stratified flow
for the gas-liquid flow in horizontal pipes are presented. Superficial velocities of each phase, as the onset of slugging
occurs, were predicted, and theoretical analysis was conducted on the stratified to slug flow regime transition. The friction,
existing between the fluid and pipe wall, and on the interface of two phases, was especially taken into account. A theoretical
model was applied to an experiment about air-oil two-phase flow in a 50 mm horizontal pipe. The effect of pipe diameter on
the transition was also studied. The results show that this approach gives a reasonable prediction over the whole range of
flow rates, and better agreement has been achieved between predicted and measured critical parameters.
__________
Translated from Journal of Shanghai Jiaotong University, 2006, 40(10): 1782–1785, 1789 [译自: 上海交通大学学报] 相似文献
20.