Zana ya Uhandisi Isiyolipisha
Kikokotoo cha Mnato wa Mafuta–Halijoto
Kokotoa mnato wa kinematic kwa halijoto yoyote kwa kutumia mlinganyo wa Walther (ASTM D341). Kielezo cha Mnato kulingana na ASTM D2270. Kiwango bora cha uendeshaji na makadirio ya kiwango cha kumwagika.
Matokeo ya Mnato
Mlingano wa Walther (ASTM D341)
Ambapo ν ni mnato wa kinematiki katika mm²/s (cSt), T ni joto kamili (K), na A, B ni vigumu vilivyoamuliwa kutoka pointi mbili za marejeleo.
Fahirisi ya Mnato (ASTM D2270)
VI compares the oil’s viscosity-temperature behavior to two reference oils: L (VI=0, naphthenic) and H (VI=100, paraffinic). Higher VI = less viscosity change with temperature.
Mfano wa Vitendo
Given: ν₄₀=68 cSt, ν₁₀₀=8.7 cSt
Walther: A=9.3097, B=3.6244
At 80°C (353.15 K): log log(ν+0.7)=9.3097−3.6244×log(353.15)=9.3097−9.2348=0.0749
ν = 10^(10^(0.0749))−0.7 = 14.7 cSt
VI ≈ 98 (mafuta ya madini ya kawaida)
Jedwali la Marejeleo la ISO VG
| ISO VG | ν kwa 40°C (cSt) | ν kwa 100°C (cSt) | Matumizi ya Kawaida |
|---|---|---|---|
| VG 10 | 10 | 2.6 | Mafuta ya spindle, mifumo ya haidroliki |
| VG 22 | 22 | 4.4 | Mifumo ya majimaji |
| VG 32 | 32 | 5.4 | Haidroliki, beari nyepesi |
| VG 46 | 46 | 6.8 | Haidroliki, beari za kawaida |
| VG 68 | 68 | 8.7 | Haidroliki nzito, gia nyepesi |
| VG 100 | 100 | 11.4 | Mzunguko wa mafuta, gia nyepesi |
| VG 150 | 150 | 15 | Gia, beari |
| VG 220 | 220 | 19 | Gia za viwandani |
| VG 320 | 320 | 24.5 | Gia nzito, gia za minyororo (worm) |
| VG 460 | 460 | 31 | Gia zenye mzigo mzito sana |
| VG 680 | 680 | 40 | Gia nzito zaidi |
| VG 1000 | 1000 | 52 | Open gears |
| VG 1500 | 1500 | 68 | Gia wazi, nyaya za chuma |
💡 Mstari bora: Mabearing mengi na gia hufanya kazi vizuri zaidi kwa 13–100 cSt. Chini ya 13 cSt kuna hatari ya msuguano wa mipaka; zaidi ya 100 cSt husababisha msongamano mkubwa wa mafuta.
