Page 147 - 《摩擦学学报》2021年第1期

144 摩 擦 学 学 报 第 41 卷

分油样的分水规律发生变化，如E、G油在室温条件 3.2.2 分水速率曲线分析
时，电容值为持续下降，而在54 ℃时却变为波动变化； 通过图4中的曲线进行一阶微分计算，绘制了各
D油在室温时电容值为波动变化，而在54 ℃时为持续 油样在54 ℃条件下的电容值变化率曲线，表达了分水

下降. 速率与时间的关系，如图5所示.

0.001 5 Oil A 1 st 0.002 0 Oil B 1 st
Rate of capacitance change/(pF/s) −0.000 5 R 0.01pF = −0.000 17 3 rd Rate of capacitance change/(pF/s) 0.001 0 3 rd
0.001 5
0.001 0
2 nd
2 nd
0.000 5
0.000 0
0.000 5
0.000 0
−0.001 0

−0.001 5 −0.000 5 R 0.01pF = −0.000 17
−0.001 0
0 400 800 1 200 1 600 2 000 0 500 1 000 1 500 2 000 2 500 3 000
Time/s Time/s

0.0020
0.001 2 Oil C 1 st 0.0015 Oil D 1 st
Rate of capacitance change/(pF/s) −0.000 2 3 rd Rate of capacitance change/(pF/s) 0.0010 3 rd
0.001 0
2 nd
0.000 8
2 nd
0.000 6
0.000 4
0.000 2
0.0005
0.000 0
0.0000
−0.000 4
R 0.01pF = −0.000 17
R 0.01pF = −0.000 17
−0.000 6
0 500 1 000 1 500 2 000 2 500 3 000 -0.0005 0 500 1 000 1 500 2 000 2 500 3 000
Time/s Time/s
0.001 5 0.000 6
0.001 0 Oil E 1 st 0.000 4 Oil F 1 st
Rate of capacitance change/(pF/s) 0.000 5 3 rd Rate of capacitance change/(pF/s) −0.000 2 3 rd
2 nd
2 nd
0.000 2
0.000 0
0.000 0
−0.000 5

−0.001 0 R 0.01pF = −0.000 17 −0.000 4 R 0.01pF = −0.000 17
−500 0 500 1 000 1 500 2 000 2 500 3 000 3 500 0 2 000 4 000 6 000 8 000
Time/s Time/s

Rate of capacitance change/(pF/s) −0.0005 R 0.01pF = −0.000 17 3 rd Rate of capacitance change/(pF/s) 0.0010 3 rd
0.0015 Oil G 1 st 0.0015 Oil H 1 st
0.0010
2 nd
2 nd
0.0005
0.0005
0.0000
0.0000

−0.0010
R 0.01pF = −0.000 17
−500 0 500 1 000 1 500 2 000 2 500 3 000 3 500 4 000 −0.0005 0 500 1 000 1 500 2 000 2 500 3 000

Time/s Time/s

Fig. 5 Variation rate of capacitance value of each oil sample at 54 ℃
图 5 54 ℃下各油样的电容值变化率曲线