共查询到17条相似文献,搜索用时 265 毫秒
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目前,红外测温技术在高温非稳态下的应用研究还不成熟,而红外测温技术的关键在于发射率的准确测量。为了测量高超声速气流下试件的温度,同时采用MCS640高温红外热像仪和GH3030高温合金热电偶对风洞马赫数5(M_a=5)中的超高强度合金结构钢D6AC劈尖试件进行温度测量。首先,通过热电偶和红外热像仪组合的匹配法校正试件的发射率,再设置热像仪的发射率,测得试件驻点的温度变化曲线和试件在不同时刻的热图。实验测得试件驻点的最高温度为2 019.3℃,对分析材料的烧蚀性能和防热结构的可靠性提供了参考。实验证明,该测温方法可以用来测量高超声速风洞中试件的温度。 相似文献
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提出了一种热像仪相对测温的性能评价方法。将薄片热电偶的热节点固定在温度场均匀的加热单元表面,作为标准辐射温度发生单元,被待评价的热像仪观测和测温,对比热像仪观测的热电偶热节点表面温度场数据和热电偶自身测得的温度数据的相似度,对热像仪相对测温性能进行评价。基于国内外4个品牌的7款不同规格热像仪进行测试,结果表明热像仪的相对测温误差和绝对测温误差相差较大,相对测温误差通常介于噪声等效温差和绝对测温误差之间,同时发现6号热像仪性能较差,温漂严重,通过装置中的A、B两靶标同时测试热像仪性能,评价结果的标准差均在8%以内,这表明该方法具有较高的可靠性,对热像仪相对测温性能评价研究有一定的参考意义。 相似文献
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通过分析红外测温公式,研究物体发射率对红外热图像测温精度的影响,并找出影响物体发射率的因素。根据经典计算方法,发现了物体发射率在红外热图像测温应用中的局限。从红外热图像的角度对发射率的计算进行了建模,基于修正物体发射率得到提高红外热图像对非稳态温度场测量精度的模型。对铸铁、不锈钢进行了3组测温实验,红外热图像直接测量的最大误差分别为2.1℃、1.7℃、2.3℃,而所提出的方法测量的最大误差分别为1.0℃、0.7℃、1.6℃。通过对比分析3组测量结果数据验证了测量方法的可行性。 相似文献
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为了研究热迟滞性对工业铂电阻温度计测量不确定度的影响,选取了8支高精度铂电阻温度计进行实验。在-50~150℃内,选择3个温度区间,采用两种标准方法(IEC 60751,ASTM E644)测量水三相点(0.01℃)和所选温度范围内的中间点的迟滞性变化。实验结果表明:4支薄膜铂电阻温度计在两种标准方法测量下,随着温度区间跨度增大,热迟滞性影响增大,IEC 60751标准方法测量的热迟滞性最大值为14.2mK,ASTM E644标准方法测量的热迟滞性最大值为20.5mK;选取4支铂丝铂电阻温度计在温度范围为-50~150℃测量时,IEC 60751和ASTM E644标准方法测量的热迟滞性数据最大值分别为1.1mK和0.9mK;铂丝铂电阻温度计热迟滞性明显小于薄膜铂电阻温度计。 相似文献
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Seung-Nam Park Yong Shim Yoo Geun Woo Lee Chul-Woung Park 《International Journal of Thermophysics》2011,32(1-2):258-268
Optical windows are indispensable for monitoring industrial processes under vacuum or high pressure by using thermal imagers and radiation thermometers. When a thermal imager observes a sample through an infrared window at elevated temperatures, the window emits additional thermal radiation and increases the background signal of the thermal images, which results in image degradation. Standard four-bar images with various radiance temperature differences were measured using a thermal imager with a spectral band from 3 ??m to 5 ??m through a UV-grade sapphire window. The four-bar images are given by a blackbody collimator with various image patterns. The window was indirectly heated in a furnace and then rapidly placed on the optical path between the collimator and the thermal imager. The four-bar image degradation was measured as a function of the window temperature and the radiance temperature difference of the four-bar pattern. A simple equation which describes the contrast of the four-bar image by using the transmittance and reflectance of the sapphire window was proposed. It was confirmed that the model can properly predict the window temperature when the appearance of the four-bar pattern cannot be determined. 相似文献
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Zhenghao Li Zhou Hu Honghu Li Shiqing Fu 《International Journal of Thermophysics》2012,33(10-11):2006-2010
A cooperative object tracking framework is proposed which shifts the priority of tracking by pose estimation based on registration between fields of view (FOVs) of different pan?Ctilt?Czoom (PTZ) thermal imagers, avoiding transferring the local features from one imager to another. When an object is selected for tracking, the related PTZ thermal imager tracks it using an improved particle filtering method, and estimates the pose of the imager simultaneously. Once the object enters an overlapping FOV of two imagers, the handoff thermal imager is activated immediately according to the spatial relationship built by pose estimation, and turns to tacking and pose estimation status. Meanwhile, the previous camera returns to waiting status for reactivation. Experiments are conducted to show the proposed framework is applicable to cooperative object tracking for PTZ thermal infrared imagers. 相似文献
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石英玻璃管大量应用于化工、机械和光学等领域, 但由于缺少精准有效的高温弹性模量评价手段, 限制了其高温热应力分析和结构设计。最近发展起来的缺口环方法可测试玻璃管材的室温弹性模量, 但其在高温下的应用因变形测量困难而鲜有报道。本研究利用相对法解决高温缺口环变形测量的难题, 从而可以方便准确地计算出高温弹性模量。采用本方法测试石英玻璃管的弹性模量并探索其在室温至1200℃间的变化规律, 发现在800℃时达到最大值87.20 GPa, 而后缓慢下降, 1100℃以后开始急剧下降。本研究显示用校正后的缺口环法测试石英玻璃管的高温弹性模量值准确、可靠, 有望推广应用于评价其他脆性圆管材料的高温弹性模量。 相似文献
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The behaviour of the cancellous bone surrogate material, rigid polyurethane foam (PUF), subject to power ultrasonic vibration excitation has been studied, with the purpose of identifying a methodology to investigate the effects that ultrasonic surgical devices have on biological tissue materials. To characterise the vibrational response to ultrasonic excitation, non‐contact measurement of the full in‐plane displacement field of PUF plate specimens was performed by combining the use of an ultra‐high speed camera and 2D digital image correlation. To investigate the thermal response, an infrared camera was used in real time to detect the temperature field. The measured surface displacement and strain fields of the PUF specimens and the thermal response are compared with data from an analytical model, and two different finite element models using Abaqus and PZFlex . The close agreement between calculated and measured data provides initial confidence in the use of the models for predicting the effects of ultrasonic excitation on tissue materials. The measurement data demonstrate the success of the experimental method for measuring vibrational responses in a hard tissue surrogate material at the ultrasonic frequencies associated with power ultrasonic surgical devices. 相似文献