利用三重积分得
(4)
5.2.2椭圆柱体的储油罐的罐容表
利用matlab分析附件一中倾斜时油面高度得到对应的储油量体积,将这些点拟合得到理论的储油量变化曲线,并与题目给出的实际的储油量的拟合曲线比较,如图3所示。
图2变位时的数据拟合曲线
通过分析附件一的数据,当油罐倾斜时,理论值与实际值的相对误差的平均值为0.03,标准差为0.01,相对稳定,且误差较小。
因此我们所建的模型是合理。
在MATLAB的环境下计算油浮子的所显示的高度
每改变
时的储油体积(即变位后的储油罐的罐容表)。
其罐容表见表1
表1储油罐变位后的罐容表(
)
油高(mm)
油量(L)
油高(mm)
油量(L)
油高(mm)
油量(L)
油高(mm)
油量(L)
油高(mm)
油量(L)
油高(mm)
油量(L)
油高(mm)
油量(L)
油高(mm)
油量(L)
0
<=1.67
310
630.1
610
1841.8
910
3112
10
3.53
320
665.6
620
1885.1
920
3151.2
20
5.94
330
701.5
630
1928.5
930
3190.1
30
9.97
340
738
640
1971.9
940
3228.6
40
14.76
350
774.9
650
2015.4
950
3266.7
50
21.04
360
812.2
660
2058.8
960
3304.4
60
27.85
370
850
670
2102.3
970
3341.7
70
36.32
380
888.2
680
2145.7
980
3378.5
80
47.56
390
926.7
690
2189.1
990
3414.9
90
63.16
400
965.7
700
2232.5
1000
3450.7
100
78.09
410
1005
710
2275.8
1010
3486.1
110
84.4
420
1044.6
720
2319.1
1020
3520.9
120
100.25
430
1084.5
730
2362.3
1030
3555.1
130
117.4
440
1124.8
740
2405.4
1040
3588.8
140
136.9
450
1165.3
750
2448.4
1050
3621.8
150
157.8
460
1206.2
760
2491.3
1060
3654.2
160
180.3
470
1247.2
770
2534
1070
3685.9
170
204
480
1288.6
780
2576.6
1080
3716.9
180
228.9
490
1330.1
790
2619.1
1090
3747.2
190
254.9
500
1371.9
800
2661.4
1100
3776.6
200
281.9
510
1413.9
810
2703.6
1110
3805.3
210
309.8
520
1456
820
2745.5
1120
3833
220
338.5
530
1498.4
830
2787.2
1130
3859.8
230
368.1
540
1540.9
840
2828.7
1140
3885.6
240
398.5
550
1583.5
850
2870
1150
3910.3
250
429.7
560
1626.3
860
2911.1
1160
3933.9
260
461.5
570
1669.2
870
2951.8
1170
3956.1
270
494
580
1712.2
880
2992.3
1180
3975.3
280
527.1
590
1755.3
890
3032.5
1190
3995.5
290
560.9
600
1798.5
900
3072.4
1200
4016.7
300
595.2
5.2问题二的模型的建立与求解
经过讨论,我们首先可将问题二的储油罐的体积看做圆柱体和两个相同球冠体的体积之和。
即
六模型的评价
优点:
在问题一中,我们从储油罐无变位与变位两个方面建立了模型,求得的储油量理论值与储油量实际值吻合得较好,相对误差小,符合要求,因此能准确的预测出罐体变位后油位高度间隔为1cm的罐容表标定值。
问题一中,主要运用积分的方法与立体几何的相关知识建立数学模型,进而求出罐内油量与油位高度之间的关系式,并利用附表中的数据对模型进行检验,结果表明得到的公式精确度足够高,可以应用于实际。
模型原理简单明了,在计算复杂积分时借助Matlab软件,提高了计算效率。
缺点:
问题一中模型我们忽略温度的改变对储油体积的影响以及油位探针,注油口管,出油管的体积对储油罐中油体积的影响,从而使得模型的误差变大。
模型仍然需要修正和完善。
七模型的改进和推广
模型的改进:
本文我们忽略了温度对油体积的影响。
因此我们可以引入环境温度的变化,减少理论值与测量值之间的误差提高准确性。
模型的推广:
本文虽然研究的是储油罐的变位识别及其罐容表标定问题,但可以推广到各种罐状容器,用类似方法建模求解。
八参考文献
[1]华东师范大学数学系编.数学分析.北京:
高等教育出版社,2008年第三版。
[2]韩中庚.数学建模竞赛获奖论文精选与点评.北京:
科学出版社,2007。
[3]江世宏.MATLAB语言与数学实验.北京:
科学出版社,2007。
九附录
MATLAB
1%进油油位高度
hi=[159.02,176.14,192.59,208.5,223.93,238.97,253.66,268.04,282.16,296.03,309.69,323.15,...
336.44,349.57,362.56,375.42,388.16,400.79,413.32,425.76,438.12,450.4,462.62,474.78,...
486.89,498.95,510.97,522.95,534.9,546.82,558.72,570.61,582.48,594.35,606.22,618.09,...
629.96,641.85,653.75,665.67,677.63,678.54,690.53,690.82,702.85,714.91,727.03,739.19,...
751.42,763.7,764.16,776.53,788.99,801.54,814.19,826.95,839.83,852.84,866,879.32,...
892.82,892.84,906.53,920.45,934.61,949.05,963.8,978.91,994.43,1010.43,1026.99,1044.25,...
1062.37,1081.59,1102.33,1125.32,1152.36,1193.49];
%累加进油量
xi=[50,100,150,200,250,300,350,400,450,500,550,600,650,700,750,800,850,900,950,1000,1050,...
1100,1150,1200,1250,1300,1350,1400,1450,1500,1550,1600,1650,1700,1750,1800,1850,1900,...
1950,2000,2050,2053.83,2103.83,2105.06,2155.06,2205.06,2255.06,2305.06,2355.06,2404.98,...
2406.83,2456.83,2506.83,2556.83,2606.83,2656.83,2706.83,2756.83,2806.83,2856.83,2906.83,...
2906.91,2956.91,3006.91,3056.91,3106.91,3156.91,3206.91,3256.91,3306.91,3356.91,3406.91,...
3456.91,3506.91,3556.91,3606.91,3656.91,3706.91];
%累加出油量
xo=[52.72,102.72,152.72,202.72,252.72,302.72,352.72,402.72,452.72,502.72,552.72,602.72,652.72,...
702.72,752.72,802.72,852.72,902.72,952.72,1002.72,1052.72,1102.72,1152.72,1202.72,1252.72,...
1302.72,1352.72,1402.72,1452.72,1502.72,1552.72,1602.72,1652.72,1702.72,1752.72,1802.72,...
1852.72,1902.72,1952.72,2002.72,2052.72,2102.72,2152.72,2202.72,2252.72,2302.72,2352.72,...
2402.72,2452.72,2502.72,2552.72,2602.72,2652.72,2702.72,2752.72,2802.72,2852.72,2902.72,...
2952.72,3002.72,3052.72,3102.72,3152.72,3202.72,3252.72,3302.72,3352.72,3402.72,3452.72,...
3502.72,3552.72,3602.72,3652.72,3702.72];
%出油油位高度
ho=[1150.72,1123.99,1101.15,1080.51,1061.36,1043.29,1026.08,1009.54,993.57,978.08,962.99,948.26,...
933.84,919.69,905.78,892.1,878.61,865.3,852.15,839.14,826.27,813.52,800.87,788.33,775.88,...
763.51,751.21,738.98,726.81,714.7,702.64,690.61,678.63,666.68,654.75,642.84,630.96,619.08,...
607.21,595.35,583.48,571.61,559.72,547.82,535.9,523.95,511.97,499.96,487.9,475.8,463.65,...
451.43,439.15,426.8,414.36,401.84,389.22,376.49,363.64,350.67,337.55,324.27,310.82,297.18,...
283.33,269.24,254.88,240.21,225.21,209.81,193.94,177.54,160.48,142.62];
hi=hi/1000;
ho=ho/1000;
xi=xi+262;
xo=xi(end)-xo;
a=0.89;b=0.6;l=2.45;
s=[];
fori=1:
length(hi)
s=[s2*a/b*quad('sqrt(0.6^2-y.^2)',-b,hi(i)-b)];
end
v=s*l*1000;
p1=polyfit([hi*1000ho*1000],[xixo],5);%拟合函数,5为阶数
p2=polyfit(hi*1000,v,5);
x1=0:
1300;
y1=polyval(p1,x1);%多项式的估值运算
y2=polyval(p2,x1);
plot(hi*1000,v,'b.',x1,y2,'b',[hi*1000ho*1000],[xixo],'r*',x1,y1,'r');
legend('理论数据','理论拟合曲线','实验数据','实验拟合曲线');
%求误差
v2=abs(v-xi)./xi;
ave=sum(v2)/length(v2);
m=max(v2);
n=min(v2);
disp(['max=',num2str(m),'min=',num2str(n),'average=',num2str(ave)]);
附录二:
求纵向倾斜时的储油罐内油量的体积和高度间隔为1cm的罐容表标定值:
symsy;
a=0.89;b=0.6;l=2.45;
%变位后累加进油量
xi=[747.86,797.86,847.86,897.86,947.86,997.86,1047.86,1097.79,1147.79,1197.73,1247.73,1297.73,1347.73,1397.73,1447.73,1497.73,1547.73,1597.73,1647.73,1697.73,1747.73,1797.73,1847.73,1897.73,1947.73,1997.73,2047.73,2097.73,2147.73,2197.73,2247.73,2297.73,2347.73,2397.73,2447.73,2497.73,2547.73,2597.73,2647.73,2697.73,2747.73,2797.73,2847.73,2897.73,2947.73,2997.73,3047.73,3097.73,3147.73,3197.73,3247.73,3297.73,3299.74];
%累加进油量的对应高度
hi=[411.29,423.45,438.33,450.54,463.9,477.74,489.37,502.56,514.69,526.84,538.88,551.96,564.4,576.56,588.74,599.56,611.62,623.44,635.58,646.28,658.59,670.22,680.63,693.03,704.67,716.45,727.66,739.39,750.9,761.55,773.43,785.39,796.04,808.27,820.8,832.8,844.47,856.29,867.6,880.06,892.92,904.34,917.34,929.9,941.42,954.6,968.09,980.14,992.41,1006.34,1019.07,1034.24,1035.36];
%累加出油量
xo=[50,100,150,200,250,300,350,400,450,500,550,600,650,700,750,800,850,900,950,1000,1050,1100,1150,1200,1250,1300,1350,1400,1450,1500,1550,1600,1650,1700,1750,1800,1850,1900,1950,2000,2050,2100,2150,2200,2250,2300,2350,2400,2450,2500,25