共查询到20条相似文献,搜索用时 203 毫秒
1.
介绍了航空发动机涡轮后气流温度传感器的现场校准方法,并对被校温度传感器的测温偏差进行了理论计算.结果表明,理论计算的结果与现场校准的结果吻合较好,说明所采用的校准方法是合理的,可以解决航空发动机涡轮后气流温度的准确测量问题. 相似文献
2.
在气流温度传感器风洞校准试验中,由于试验成本高、校准试验环境与实际使用环境差距大等原因,有必要构建气流温度传感器数值校准虚拟风洞,实现极限非常规校准工况的气流温度传感器误差修正及虚拟校准,并通过气流温度传感器的虚拟校准数值风洞获取仿真结果,尽可能地减少实物校准的工况数量,同时也从理论层面为气流温度传感器的设计与校准提供... 相似文献
3.
4.
5.
以双屏吹气式热电偶为基本结构,采用计算与试验相结合的方式,设计了一种适用于航空发动机试车台现场的K型参考温度传感器,用以对现场测温的传感器进行校准,以期解决涡轮后气流温度传感器的校准问题,并为此类参考温度传感器的设计提供一定的参考. 相似文献
6.
为了确定温度传感器辐射修正校准的准确性,需要对温度传感器辐射修正校准结果进行对比及不确定度分析.本文介绍了在热校准风洞中进行温度传感器辐射修正校准的结果,并做了对比研究和不确定度分析. 相似文献
7.
8.
为了提高旋转盘腔温度和压力测试的准确性,开展温度补偿和压力修正方法研究。针对旋转盘腔温度测试时,滑环引电器普通导线无法产生电势差导致测温误差较大的问题,提出了温度补偿方法,将温差转换为电势差补偿到输出电势中,之后根据热电偶电势与温度的关系计算得到测量端真实温度;针对旋转盘腔旋转状态下,引压管中的空气柱产生管涌效应导致低半径处的传感器产生测量误差的问题,提出了压力修正方法,将管内空气柱进行分段,每段视作均温气体,推导得到压力修正公式。开展试验对所提出的温度补偿和压力修正方法的应用效果进行验证,结果表明:对热电偶测温结果进行补偿后,误差低于1%;对压力测量结果进行修正后,相对偏差不超过0.8%,且转速越高,压力修正效果越明显。修正后的温度和压力精度满足航空发动机旋转盘腔实际测量需求,证明了所提出方法的准确性,为航空发动机转子的寿命评估提供了重要技术支撑。 相似文献
9.
经典的短波高温修正模型不适用于中长波红外温度计的发射率修正和不确定度评定。采用有效亮度温度概念,得到了对于温度范围和测温波长具有广泛适用性的发射率影响模型以及具有简明物理含义的微差近似形式,包含了经典亮度温度理论中的发射率影响修正和环境辐射误差修正。定量分析了经典的短波高温修正模型的误差。针对黑体辐射源的不同溯源方法,讨论了辐射温度计校准中的发射率影响修正方法,并给出修正实例。所用方法可用于辐射测温应用、辐射温度计校准和黑体辐射源校准中的发射率和环境影响修正以及辐射源发射率不确定度对校准结果不确定度贡献的计算。 相似文献
10.
11.
12.
13.
智能控制技术与互联网技术在房间空调系统应用的基础是对其性能的在线实时监测。本文提出一种房间空调系统性能在线监测的方法。首先将空调器布置温度测点采集到的换热器铜管表面温度和电流电压等电路参数结合,转化为制冷循环中制冷剂的状态参数;再通过压缩机流量半经验计算模型计算制冷剂的质量流量,进而得出室内机中制冷剂侧的换热量;最后结合电路参数求得的整机功率,实现房间空调系统制冷量、制热量、功率、能效的实时监测。结果表明:采用此方法计算房间空调器性能参数的最大偏差小于15%,主要误差来源为蒸发压力的计算误差。 相似文献
14.
换能器的指向性测试是其声学性能测试的基本项之一。文章对换能器的指向性测试时,声中心与机械装置的旋转中心存在偏差的情况进行分析,并采用极坐标下矢量运算的方法进行理论分析和仿真,得出该偏差会直接对测试结果引入幅度与角度偏差,使全指向性换能器指向性图形成类似心形的指向性图,并得到了一种换能器指向性图修正方法。实测结果表明:当声中心与机械装置的旋转中心存在偏差时,换能器指向性响应测试及指向性开角的判读会存在偏差,同时文中提出的指向性图修正方法对此工况下的测试结果有较好的修正效果,有助于提高水声换能器指向性测量的精度,且具有良好的工程适用性。 相似文献
15.
S. Ljungblad L. E. Josefson M. Holmsten 《International Journal of Thermophysics》2011,32(11-12):2495-2503
A highly automated calibration method for temperature loggers is presented. By using an automated procedure, a time- and cost-efficient calibration of temperature loggers is made possible. The method is directed at loggers that lack the function/property of direct reading from a display. This type of logger has to be connected to a computer for the setting-up of the measurement and again for collection of the measurement results. During the calibration, the loggers are offline. This method has been developed for temperature loggers from Gemini Data loggers, but the software and method could be modified to suit other types of loggers as well. Calibration is performed by comparison to a reference thermometer in liquid baths; and for loggers which have external sensors, only the sensor is normally placed in the bath. Loggers with internal sensors are protected from the liquid by placing them in an exterior plastic or metallic cover, and thereafter the entire loggers are placed in the bath. A digital thermometer measures the reference temperature of the bath and transmits it to a computer by way of Bluetooth. The developed calibration software, SPTempLogger, controls the logger software, and thus the communication protocol of the logger software does not need to be known. The previous method, with manual handling of the start and termination of every measuring sequence, evaluation of the resulting data and its corresponding uncertainty components, can be replaced by this automated method. Both the logger and reference measurement data are automatically downloaded once the logger has been connected to a computer after the calibration, and the calibration software started. The data are then evaluated automatically, and by statistical analysis of the confidence coefficient and standard deviation, the temperature plateaus that the calibration includes are identified. If a number of control parameters comply with the requirements, then the correction, resolution, and short-term stability are calculated for each calibration temperature. The calculated values are saved in a database, along with information about the instruments used during the calibration, after which calibration certificates and measurement uncertainty calculations can be generated. Up to ten loggers can be connected at the same time and are then evaluated in sequence. The paper will show that the system can correctly analyze different types of measurement sequences and what measurement uncertainties are associated with this. 相似文献
16.
拉伸试验能力验证结果的稳健统计指定值及其不确定度 总被引:1,自引:0,他引:1
佟艳春 《理化检验(物理分册)》2010,(2):79-83
利用金属材料室温拉伸试验能力验证结果的中位值作为初始稳健平均值,用其稳健标准偏差对其进行修正得到修正后的稳健平均值及稳健标准偏差,以此方法反复修正直至稳定,得到能力验证结果的指定值,最后再根据稳定后的稳健标准偏差计算指定值的不确定度。结果表明:对该次拉伸试验结果进行二次修正后,其稳健平均值及稳健标准偏差均已稳定,分别为799和6.23 N·mm~(-2);因此该次金属材料室温拉伸试验能力验证结果的指定值为799 N·mm~(-2);该指定值的标准不确定度为0.7,N·mm~(-2)。 相似文献
17.
A method of measuring static and pulsed pressures using electrically conducting rubber sensors is proposed. The method is
based on a change in the volume resistivity of a filled rubber under the action of external pressure. The pressure-induced
change in resistance of the rubber sensor is proportional to the applied pressure and can be measured by a bridge circuit.
Using this method, it is possible to evaluate the degree of homogeneity of the pressure distribution over a solid surface.
This is achieved by distributing rubber sensors over the given surface. 相似文献
18.
本文总结了现具有较高认可度且具有相当预测精度的空气侧换热特性的理论预测模型,选用常规平直铝翅片铜管换热器在典型的空调工况(空气干球温度为27℃,湿球温度为19. 5℃,换热器迎面风速为1~4 m/s,入口水温为7~13℃,流速为1. 8 m/s)下,对现有模型在低气压环境(40~100 kPa)下的适用性进行分析研究。实验研究表明:在试验工况下,随着换热器所处环境压力的降低,常压模型预测值与实验值的偏差急剧增加至127. 4%~-36. 6%,且常压模型预测值普遍偏大。同时低气压环境下管排数的影响依然存在,且更加显著。基于本文实验数据对3个常压模型进行环境气压修正后,预测精度大幅提高:在试验工况下,最大偏差分别降至32. 63%、24. 91%和21. 74%,平均偏差为1. 79%、-2. 90%和-8. 59%,在±20%的误差带内修正模型预测精度比分别达到90. 97%、93. 75%和88. 96%。 相似文献
19.
目的 针对纸塑复合袋在传输过程中褶皱、跑偏等问题,提出一种基于磁力压紧装置的纸塑复合袋纠偏系统.方法 首先根据磁力压紧纠偏原理设计一套纠偏系统;然后基于显式动力学有限元接触理论,对不同影响因素下纸塑复合袋的形变进行有限元仿真分析;最后搭建实验平台,并测量纸塑复合袋的形变,验证仿真结果.结果 在此计算工况下得到了较优方案,纸塑复合袋与皮带间的动摩擦因数为0.25,磁压力为7 N,皮带间的间距为476 mm.结论 实验平台得到的结果与仿真结果基本一致.根据实验结果改进的磁力纠偏系统能够应用于纸塑复合袋的纠偏,满足工业生产需求. 相似文献
20.
Yuji Yoshie Masanori Ishizuka Guoqing Guan Chihiro Fushimi Atsushi Tsutsumi 《Advanced Powder Technology》2013,24(2):487-494
A novel method for directly measuring the temperature history of mobile hot ferromagnetic particles (steel particles), substituting for reacting particles, in a binary-solid (reacting particles and inert particles) downflow is introduced. The temperature history of the hot steel particles can be obtained by measuring the temperature of the particles at different axial positions using magnetic fields that can separate the steel particles from other bed materials immediately and easily. Employing the magnetic marking method, magnetic sensors were used to detect the change in magnetic flux density in a given magnetic field, and the residence time of the steel particles was also measured. The cross-sectional averaged particle-to-bed heat transfer coefficients were calculated from the experimental results using simple heat balance equations. The measured temperature data have a relatively wide error range; however, the average temperature curves derived from the average particle-to-bed heat transfer coefficients agreed with the temperature plots. Therefore, the experimental method of this study is applicable to the measurement of the particle temperature in a binary-solid downflow. The results showed that there is strong correlation between the particle-to-bed heat transfer coefficients and normalized collision frequency under the laminar gas flow conditions. 相似文献