1. Power Machinery Vehicular Engineer Institute, Zhejiang University, Hangzhou 310058, China 2. Shanghai Marine Diesel Engine Research Institute, Shanghai 201108, China
The experimental platform for two-phase flow oscillating flow visualization experiment was designed and established, by using 3D printing technology to restore the cooling gallery in a certain type of diesel engine piston. For the two different cooling media, glycerin aqueous solution and soybean oil, oil output data was collected and the oil pass rate was calculated while the flow field images were taken visually. The oil data was collected and the pass rate was calculated while taking visual image of flow field for two different fluid medium. Results show that the proposed test method can abandon the spray splash interference, collect the oil output data, obtain a clear and identifiable visual image. The photographic results were compared and analyzed, and the flow patterns of two-phase flow oscillating flow were identified and classified. As results, when the Reynolds number is above 20 000, the flow state of the two-phase flow oscillating flow changes significantly and enter strong turbulent state.
Fig.13D model of piston cooling gallery and installation method of test pieces
Fig.2Schematic diagram of two-phase flow oscillation visualization experimental platform
Fig.33D model of fuel injection nozzle
冷却介质
$\rho $/(kg·m?3)
$\nu $/(N·s·m?2)
甘油水溶液
1 260
0.016 8
大豆油
920
0.068 5
Tab.1Physical parameters of cooling medium
Fig.4Flow patterns of glycerol aqueous of BDC piston cooling gallery at different rotation speeds with injection flow rate of 0.015 kg/s
Fig.5Flow patterns of glycerol aqueous of piston cooling gallery at different crank angles and different rotation speeds with injection flow rate of 0.025 kg/s
序号
N/(r·min?1)
$V$/mL
${t_0}$/s
${Q_{{\rm{out}}}}$/(mL·s?1)
$\phi $/%
$\overline \phi $/%
1
200
302
1.74
17.48
89.62
91.49
2
264
17.32
88.81
3
298
18.73
96.05
4
300
240
1.45
15.82
81.12
82.83
5
254
15.87
81.38
6
236
16.77
86.00
7
400
230
1.07
15.88
81.44
79.42
8
218
14.38
73.74
9
247
16.20
83.08
10
500
202
0
11.78
59.94
52.77
11
220
10.06
51.59
12
228
9.12
46.79
13
600
184
0
9.32
47.82
43.69
14
187
8.46
43.37
15
178
7.78
39.89
Tab.2Test data of glycerol aqueous solution with flow rate of 0.025 kg/s
Fig.6Comparison of pass rate of glycerin aqueous solution and soybean oil
Fig.7Flow patterns of soybean oil when piston cooling gallery is at TDC and BDC at different rotation speeds with pump pressure of 0.5 MPa
N/(r·min?1)
v/(m·s?1)
Re
甘油水溶液
大豆油
实机机油
200
2.31
10 568
1 893
7 129
300
3.46
15 830
2 835
10 679
400
4.62
21 137
3 785
14 259
500
5.77
26 398
4 727
17 808
600
6.93
31 704
5 678
21 388
1 858
20.78
—
—
64 134
Tab.3Reynolds number of glycerin aqueous solution,soybean oil and engine oil at different rotation speeds
N/(r·min?1)
$Re$
N/(r·min?1)
$Re$
400
14 042
800
28 085
500
17 553
900
31 595
600
21 063
1 000
35 106
700
24 574
?
?
Tab.4Reynolds number of straight piston gallery experiment at different rotation speeds
Fig.8Reynolds number and flow patterns correspondence table
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