共查询到20条相似文献,搜索用时 187 毫秒
1.
2.
3.
4.
制冷剂闪蒸瞬态喷雾冷却已经成为激光治疗葡萄酒色斑临床手术中重要的冷却辅助手段,能够保护表皮不受激光的热损伤,提高治疗激光能量,改善治疗效果。针对制冷剂闪蒸瞬态喷雾冷却表面温度快速准确测量的难点,建立了制冷剂闪蒸喷雾冷却实验系统,利用磁控溅射技术直接在被测表面沉积T型薄膜热电偶,对薄膜热电偶测量瞬态表面温度技术进行了详细研究,校核了薄膜热电偶的静态温度特性和动态反应时间,对测得的温度结果进行了巴特沃斯低通滤波处理,比较了滤波截止频率和采样率对滤波结果的影响。 相似文献
5.
喷雾冷却在工业过程中应用广泛,制冷剂喷雾是激光皮肤手术中实施表皮冷保护的必要手段。为提高冷却效率,需要通过表面温度的测量反推表面传热特性。为探索不同表面温度测量方式对实验结果的影响,搭建了瞬态喷雾冷却实验台,分别使用磁控溅射薄膜热电偶(TFTC)、丝状热电偶(FTC)和片状热电偶(STC)研究了R404A制冷剂喷雾环氧树脂表面传热特性的差异。实验结果表明,磁控溅射薄膜热电偶(TFTC)热响应性能最佳,能准确及时地反映表面温度的瞬态变化且可与热通量变化准确对应。丝状热电偶(FTC)和片状热电偶(STC)属于间接测温,温度变化存在明显滞后,影响热通量、对流传热系数等表面传热特性的精确分析。薄膜溅射热电偶测温是准确研究瞬态喷雾冷却表面传热过程的可靠手段,可为临床治疗提供理论指导。 相似文献
6.
温度出现阶段变化时,热电偶的输出变化至相当于该阶段的某个规定百分数所需的时间称为热电偶的响应时间。测量热电偶的热响应时间比较复杂,不同的实验条件会有不同的测量结果,这是因为它受热电偶与周围介质的换热率影响,换热率高,则热响应时间就短。 相似文献
7.
基于USB-4716的工业热电偶自动检定系统设计 总被引:1,自引:0,他引:1
针对工业中常用的温度采集、处理系统的分析,利用USB-4716数据采集模块对热电偶检定过程中加热炉温度进行采集和处理,通过对热电偶锌、铜和铝3个检定点热电动势的采集和误差分析,判定被检热电偶是否合格,进而给出检定报表。整个过程结合计算机控制技术,实现了热电偶自动检定、数据存储、报表打印以及历史记录查询等功能。 相似文献
8.
9.
23 无机传热管在传热过程中表面温度如何 ?大连新QU能源有限公司曾对无机传热管在传热时表面温度分布状况做了以下 3种实验 :( 1 )在水的强制对流散热条件下均温特性实验 实验装置及原理说明 :实验采用的微型无机热传导元件由铜材制成 ,在元件加热端用两支棒状电热体加热 ,中间段隔热 ,冷却段设两个水循环装置 ,在元件的外壁面 (见图 1 ) ,埋设 7支K型热电偶。热电偶的信号通过日本横河DA1 0 0型仪器采集数据。将采集数据转换成温度信号后传递到计算机 ,计算机可将测试结果打印出来。实验结论 :微型无机热传导元件热阻趋于零 ,均温性… 相似文献
10.
提出了一种改进的磨削温度测量方法。与传统的方法不同之处在于,该方法是利用导热膏将工件表面温度传递给热电偶。采用三种方法测量了碳纤维复合材料的磨削温度。从实验结果可以看出,改进的磨削温度测量方法完全可以替代传统的夹丝法,很适合测量碳纤维复合材料的磨削温度。 相似文献
11.
本文运用有限元法,采用二次等参单元,对注塑模二维非稳态温度场进行了数值分析,推导了有限元数值求解方程并研制了有限元求解程序软件。实例所得温度场等温线与实验所得结果基本相符,验证了计算机求解的可靠性。通过计算机模拟分析,可了解各瞬时模具温度场的分布状态,观察模具体能否使塑件均匀冷却,如不合理,可通过改变冷却管道参数,达到温度场均匀一致,从而提高塑件质量。通过程序运转,根据塑件的热定型温度,可以预知最短冷却时间,从而缩短冷却周期,提高塑件生产率 相似文献
12.
The effect of molecular weight on the spherulite growth rate of poly(ethylene terephthalate) (PET) has been determined using a real-time small angle light scattering (RTSALS) device equipped with a two-dimensional position-sensitive detector. This detector, the design of which was previously reported, incorporates a CCD camera, a personal computer, and an imaging board as the major hardware components. The device performs real-time analysis of the light scattering pattern and calculates the average spherulite radius as a function of time during the crystallization experiment. Growth rate data were obtained for PET having number-average molecular weights of 18,000, 24,700, and 33,100. Samples were crystallized isothermally following a temperature jump from the glass at room temperature to the desired crystallization temperature, which ranged from 130 to 200°C. Both the temperature and molecular weight dependence were found to be well described by the Hoffman equation. The temperature dependence agrees well with that found by previous workers, but the molecular weight dependence is somewhat different. 相似文献
13.
14.
15.
Because of the introduction of new processing parameters in water-assisted injection molding (WAIM), processes control has become more difficult. First, design of experiment (DOE) was carried out by using optimized Latin hypercubes (Opt LHS). On the basis of this, computational fluid dynamics (CFD) method was used to simulate and calculate hollowed core ratios and wall thickness differences of cooling water pipe at different positions. Then inverse radial basis function (RBF) neural network model reflecting the fitting relationship between processing parameters and molding quality was established, and accuracy of the model was detected by cross validation. Finally, expected molding quality was applied to predict processing parameters, and the obtained molding quality under the predicted processing parameters was verified by computer aided engineering (CAE) simulation and experimental methods. The results showed that mean relative precisions of processing parameters such as melt temperature, delay time, short shot size, water pressure, and mold temperature for inverse RBF model were 98.6%, 93.6%, 98.5%, 93.9%, and 97.9%, respectively, which met the accuracy requirements. Furthermore, compared with expected values of hollowed core ratios and wall thickness differences, the average errors of CAE and experiment were 2.3% and 4.9%, respectively. 相似文献
16.
17.
18.
以丁酮肟为封闭剂,制备了封闭型多异氰酸酯树脂;通过实验,讨论了丁酮肟与异氰酸酯基团的摩尔比、反应温度、反应时间对封闭反应的影响;并通过红外光谱研究了封闭产物解封温度。结果表明,最佳反应条件为n(丁酮肟)/n(-NCO)为1.2,反应温度60℃,反应3 h,且封闭物在120℃左右可以解封。 相似文献
19.