Research of the measurement method for the pressure distribution along the micro/mini-channel
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摘要: 设计并搭建了一套微小通道沿程压力的测量系统,包括PMMA通道和压力方腔、微应变传感器及多通道应变仪等。利用注射泵的推进方法提供微通道静压,采用FCO510型高精度微差压计的测量值作为标准压力,通过多通道应变仪测量微通道方腔中各个应变片的应变值,从而建立标准压力和应变之间的标定函数。分别对3种微压芯片在80、70、60及50mL/min等4种不同流量下的压力分布进行了测量,压力分布具有良好的线性规律。不确定度分析表明压力误差的相对扩展不确定度范围为0.15%~6.82%,测量结果的有效性和可靠性较高。Abstract: In this study, a system was designed and built up for the pressure measurement along micro/mini-channel, which mainly includes micro/mini-channel and square pressure cavities on PMMA chip, micro-strain sensors and multi-channel strain instruments. The static pressure in micro/mini-channel was provided by the syringe pump, and the high precision pressure values measured by the micromanometer of FCO510 was employed as the standard pressure. The strain values from the strain sensors installed on the square pressure cavities were obtained by multi-channels strain gauge, and the calibration functions between the standard pressure and the strain were established. The pressure distributions of three kinds of micro pressure chips were measured under flow rates of 80, 70, 60 and 50mL/min, respectively. The pressures have good linear distribution.The uncertainty analysis indicates that the relative uncertainty of the pressure error is between 0.15% and 6.82%. The validity and reliability of pressure measurement are high.
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Key words:
- micro/mini-channel /
- pressure along the channel /
- strain measurement /
- uncertainty
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表 1 DH3818N-2型应变仪参数
Table 1. Strain instrument parameters of DH3818N-2
参数 技术指标 测量通道数 20 适用应变片电阻值 50~10000Ω 应变片灵敏度系数 1.0~3.0自动修正 采样速率 2Hz/通道 测量应变范围 ±30000με 系统示值误差 不大于0.5% 最高分辨率 0.5με 表 2 3组微压芯片尺寸参数
Table 2. Scales of three kinds of pressure chip
芯片 芯片尺寸/mm 通道尺寸/mm 方腔尺寸/mm Type1 80×30×4 68×2.5×1 4×1.5×1 Type2 80×30×4 68×1.5×1 3×1.5×1 Type3 80×30×4 58×1×0.5 2×1×0.5 表 3 2种型号应变片的主要参数
Table 3. The main parameters of two strain gauges
参数 KFG-1 KFG-5 基底尺寸/mm 4.8×2.4 9.4×2.8 敏感栅长/mm 1 5 电阻值/Ω 120.4±0.4 119.6±0.4 灵敏度系数/% 2.13±1 2.09±1 表 4 第1组所有测点压力测量不确定度评定结果
Table 4. Uncertainty evaluation results of all pressure measurement points of type 1 channel
测点距离
/mm测量不确定度/% 流量
80mL/min流量
70mL/min流量
60mL/min流量
50mL/min5 2.16 0.45 0.96 2.71 10 0.68 1.87 1.03 0.83 15 1.32 0.52 0.26 0.75 20 1.51 2.98 2.57 1.24 25 2.94 3.01 3.81 3.08 30 1.27 1.34 1.89 1.39 35 3.84 3.73 2.75 3.79 40 2.11 1.29 0.94 2.13 45 3.76 2.84 3.76 3.88 50 4.18 5.17 6.13 1.91 55 3.97 3.26 2.32 5.46 60 6.53 6.02 4.75 5.73 表 5 第2组不同测点压力测量不确定度评定结果
Table 5. Uncertainty evaluation results of all pressure measurement points of type 2 channel
测点距离
/mm测量不确定度/% 流量
80mL/min流量
70mL/min流量
60mL/min流量
50mL/min5 2.05 2.49 2.08 2.17 10 1.62 1.86 1.07 2.38 15 1.96 0.36 2.43 0.29 20 0.77 1.03 1.75 1.04 25 0.84 2.68 2.16 3.18 35 1.04 1.39 1.18 0.36 40 3.27 3.12 2.94 3.77 45 2.83 1.18 1.36 1.64 50 4.65 3.42 6.76 6.73 55 3.29 2.07 1.61 5.41 60 6.73 5.26 6.82 4.95 表 6 第3组不同测点压力测量不确定度评定结果
Table 6. Uncertainty evaluation results of all pressure measurement points of type 3 channel
测点距离/mm 测量不确定度/% 流量
80mL/min流量
70mL/min流量
60mL/min流量
50mL/min5 1.84 2.67 1.06 1.05 10 1.03 1.85 0.15 1.13 15 0.96 0.33 1.04 0.98 20 0.31 1.27 0.51 1.02 25 1.26 2.64 1.46 1.39 30 0.28 0.58 1.52 2.04 35 1.13 1.35 0.27 2.18 40 4.84 5.62 4.89 4.96 45 5.16 4.17 5.63 0.83 50 0.72 3.43 6.12 4.64 -
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