Viscosity. The ọnụọgụ nke ike viscosity. The anụ ahụ pụtara nke ọnụọgụ nke viscosity

viscosity index - a isi oke nke na-arụ ọrụ ọmụmụ ma ọ bụ gas. Na anụ ahụ okwu, na-viscosity nwere ike kọwaa dị ka esịtidem esemokwu mere site ngagharị nke ahụ emejupụta uka nke mmiri mmiri (gaseous) na-ajụ, ma ọ bụ, ndị ọzọ nanị, ije eguzogide.

Gịnị bụ viscosity

A mfe ahụrụ anya ahụmahụ viscosity mkpebi siri ike: ire ụtọ sloped n'elu n'out oge wụsara n'ime ihe hà ego nke mmiri na mmanụ. Mmiri aga ngwa ngwa mmanụ. Ọ bụ ihe ọmụmụ. N'ịga ngwa ngwa igbapu mmanụ na-egbochi a elu esemokwu n'etiti ya na ụmụ irighiri (esịtidem eguzogide - viscosity). N'ihi ya, ọmụmụ viscosity inversely proportional ya fluidity.

viscosity index: usoro

Na a dị mfe odidi nke usoro nke viscous ọmụmụ na mmetụta dị aṅaa nwere ike ga-atụle ka ewepụghị ukem n'ígwé A na B na otu n'elu ebe S, anya n'etiti nke bụ ịdị ukwuu nke h.

Abụọ ndị a n'ígwé (A na B) akpali iche iche na velocities (V na V + ΔV). A oyi akwa na-enwe ndị kasị elu ọsọ (V + ΔV), na-agụnye ije nke oyi akwa B, na-akpụ akpụ na a iji nwayọọ ọsọ (V). N'otu oge ahụ na-B oyi akwa nēche ịkụda ọnụego nke oyi akwa A. The anụ ahụ pụtara nke viscosity ọnụọgụ bụ na esemokwu nke ụmụ irighiri emejupụta eruba-eguzogide nke n'ígwé Nleta a ike nke Isaak Nyuton kọwara ndị na-esonụ usoro:

F = μ × S × (ΔV / h)

ebe a:

• ΔV - iche n'etiti ọsọ nke ije nke ọmụmụ eruba n'ígwé;
• h - anya n'etiti mmiri mmiri iyi n'ígwé;
• S - n'elu ebe nke ọmụmụ eruba oyi akwa;
• μ (mu) - akpata dabere na Njirimara nke a mmiri mmiri, na-akpọ zuru ike viscosity.

Na SI nkeji usoro bụ dị ka ndị:

μ = (F × h) / (S × ΔV) = [Pa × s] (× onwa nke abụọ)

Ebe F - ike nke ike ndọda (arọ) unit nke haịdrọlik ọmụmụ olu.

uru nke viscosity

N'ọnọdụ ka ukwuu, na ọnụọgụ nke ike viscosity tụrụ na centipoises (CP) dị na usoro cgs (sentimita, gram, nke abụọ). Na omume, nke viscosity nke mmiri mmiri uka ruru na-metụtara ya olu, i.e. mmiri mmiri njupụta:

ρ = m / V

ebe a:

• ρ - njupụta nke mmiri mmiri;
• m - uka nke ọmụmụ;
• V - olu nke mmiri mmiri.

The ruru n'etiti ike viscosity (μ) na njupụta (ρ) a na-akpọ a kinematic viscosity ν (ν - Greek - nu):

ν = μ / ρ = [m ² / s]

Itunanya bu na, ụzọ maka ịchọpụta na viscosity ọnụọgụ dị iche iche. Ka ihe atụ, ndị kinematic viscosity ka na tụrụ na dị na GHS usoro ke centistokes (CST) na a submultiple quantities - Stokes (St):

• 1st Class = 10 ^-4 m ² / s = 1 cm ² / s;
• 1sSt = 10 ^-6 m ² / s = 1 mm ² / s.

Mkpebi siri ike nke viscosity nke mmiri

Viscosity ọnụọgụ nke mmiri kpebisiri ike site na odomo ọmụmụ eruba oge site na calibrated capillary tube. Ngwaọrụ a calibrated eji a mara ọkọlọtọ mmiri mmiri viscosity. Iji chọpụta kinematic viscosity, tụrụ na mm ² / s, ọmụmụ eruba oge, tụrụ na sekọnd, na-uba site a mgbe nile uru.

Dị ka a tụnyere unit na-eji na-viscosity nke distilled mmiri, onye bara uru bụ fọrọ nke nta mgbe nile, ọbụna mgbe okpomọkụ mgbanwe. Viscosity - a ruru nke oge na sekọnd a chọrọ ofu olu nke distilled mmiri ka Mmebi nke a calibrated onu, na otu uru maka ule mmiri mmiri.

viscometers

Viscosity tụrụ na degrees Engler (Celsius E) Saybolt Universal Sekọnd ( "sus) ma ọ bụ Redwood degrees (Celsius RJ) dabere na ụdị nke rheometer. Three ụdị viscometers iche naanị na ego nke mmiri na-asọ mmiri mmiri na-ajụ.

Viscometer odomo viscosity na European unit Engler degrees (Celsius E), gbakọọ kwa 200 cm ³ nke mmiri na-asọ mmiri mmiri na-ajụ. Viscometer odomo viscosity na Saybolt Universal Sekọnd ( "sus ma ọ bụ" SSU), na-eji na United States, nwere 60 cm ³ nke ule mmiri mmiri. Na England, ebe eji Redwood degrees (Celsius RJ), enịmde viscometer odomo viscosity nke 50 cm nke ³ nke mmiri mmiri. Ka ihe atụ, ọ bụrụ na 200 cm ³ si mmanụ aga na ugboro iri iji nwayọọ karịa otu ego nke mmiri, viscosity bụ 10 Celsius Engler E.

Ebe ọ bụ na okpomọkụ bụ isi ihe na-akpata na-agbanwe agbanwe viscosity ruru, ndị nha na-na-emekarị rụrụ ibido na a mgbe nile okpomọkụ nke 20 ° C na mgbe na ya elu ụkpụrụ. The N'ihi ya, na otú a, a na-egosipụta site na-agbakwụnye ihe kwesịrị ekwesị okpomọkụ, e.g. 10 Celsius E / 50 ° C ma ọ bụ 2.8 Celsius E / 90 Celsius C. mmiri mmiri viscosity na 20 ° C elu karịa ya viscosity na elu okpomọkụ. Hydraulic mmanụ nwere a viscosity na ndị na-esonụ iche okpomọkụ:

190 CST na 20 ° C = 45,4 CST na 50 ° C = 11,3 CST na 100 Celsius C.

translation ụkpụrụ

Mkpebi siri ike nke viscosity n'akparamagwa dị iche iche na usoro (American, British, GHS), ya mere na-achọkarị ịsụgharị data site na otu e ji atụ usoro ọzọ. Iji tọghata ụkpụrụ nke viscosity nke ọmụmụ kwupụtara na degrees Engler na centistokes (mm ² / s) iji na-esonụ ahụrụ anya usoro:

ν (CST) = 7,6 × ° E × (1-1 / Celsius E3)

Dị ka ihe atụ:

• 2 Celsius E = 7,6 × 2 × (1-1 / 23) = 15,2 × (0.875) = 13,3 CST;
• 9 Celsius E = 7,6 × 9 × (1-1 / 93) = 68,4 × (0,9986) = 68,3 CST.

Iji ngwa ngwa ikpebi ọkọlọtọ viscosity nke haịdrọlik usoro nwere ike mfe mmanụ dị ka ndị a:

ν (CST) = 7,6 × ° E (mm ² / s)

Inwe ν kinematic viscosity na mm ² / s ma ọ bụ CST, ọ nwere ike converted n'ime a ike viscosity ọnụọgụ μ, iji na-esonụ mmekọrịta:

μ = ν × ρ

Atụ. Chịkọta iche iche formulas translation Engler degrees (Celsius E) centistokes (CST) na centipoises (cps), iche na haịdrọlik mmanụ a njupụta ρ = 910 kg / m ³ nwere a kinematic viscosity nke 12 Celsius E, na nkeji nke centistokes:

ν = 7,6 × 12 × (1-1 / 123) = 91,2 × (0,99) = 90,3 mm ² / s.

Ebe ọ bụ na 1sSt = 10 ^-6 m ² / s na 1br = N × 10 ^-3 s / m ^2, mgbe ahụ ike viscosity ga-hà:

μ = ν × ρ = 90,3 × 10 ^-6 · 910 = 0.082 × N s / m ² = 82 cPs.

Viscosity ọnụọgụ nke gas

Ọ na-ekpebisi ike site na mejupụtara (chemical, n'ibu) gas ka okpomọkụ na nsogbu etinyere na gas-ike mgbawa metụtara na gas ije. Na omume, nke viscosity nke gas na-sonye na akaụntụ ke imewe mmepe nke gas ubi, ebe na ngụkọta oge na-ekenịmde ọnụọgụ mgbanwe dabere na gas mejupụtara mgbanwe (mkpa karịsịa maka gas ghọọ mmanụ ego), okpomọkụ ma na nsogbu.

Anyị gbakọọ ọnụọgụ nke viscosity nke ikuku. The Filiks ga-adị ka ihe ndị a kọwara n'elu abụọ mmiri aga. Iche yiri akpụ akpụ abụọ gas iyi U1 na U2, ma n'ọtụtụ dịgasị iche iche. N'etiti n'ígwé convection ga-eme (interpenetration) ụmụ irighiri. N'ihi ya, ọkụ ngwa ngwa na-akpali akpali ikuku eruba ga ibelata na ibido na-akpụ akpụ ji nwayọọ nwayọọ na - accelerated.

The ọnụọgụ nke viscosity nke ikuku, dị ka Newton iwu, kwupụtara na-esonụ usoro:

F = -h × (du / dZ) × S

ebe a:

• du / dZ bụ ike ọsọ grajentị;
• S - ebe mmetụta ike;
• Lekọtara h - di omimi viscosity.

viscosity index

Viscosity Index (VI) - a oke correlating mgbanwe viscosity na okpomọkụ. The mmekọrịta bụ a mgbakọ na mwepụ na nduzi mmekọrịta, na nke a abụọ ụkpụrụ na nke okpomọkụ mgbanwe a na-esonyere Ịhazi mgbanwe nke viscosity. The elu viscosity index, na obere mgbanwe n'etiti abụọ ụkpụrụ, i.e. na viscosity nke na-arụ ọrụ ọmụmụ bụ ndị ọzọ mụ na okpomọkụ.

The viscosity nke mmanụ

Na ntọala nke oge a mmanụ viscosity index erughị 95-100 nkeji. Ya mere, na haịdrọlik ígwè na akụrụngwa nwere ike ji mee zuru ezu anụ oke mmiri na-igbochi obosara mgbanwe viscosity n'okpuru ọnọdụ nke oké egwu okpomọkụ.

"Mma" ọnụọgụ nke viscosity nwere ike nọgidere na-enwe site na-ewebata a pụrụ iche mmanụ nwekwara (Polymers) nwetara site na distillation nke mmanụ ala. Ha dịkwuo viscosity index mmanụ site na ịmachi mgbanwe àgwà nke ime nso. Na omume iwebata mkpa nke ukwu nke nwekwara ndị ala viscosity index isi mmanụ nwere ike zụlitere ka 100-105 nkeji. Otú ọ dị, ọ na-enweta ngwakọta bụ gaghịzi ya Njirimara n'okpuru elu nsogbu na okpomọkụ ibu, si otú mbenata irè nke mmako.

Na ike na sekit na sekit a ga-eji ike haịdrọlik oke mmiri na a viscosity index nke 100 nkeji. Oke mmiri nwere nwekwara na dịkwuo viscosity index, na-eji haịdrọlik akara na sekit na sekit na ndị ọzọ na usoro na-arụ ọrụ na nso nke ala / usoro nsogbu, na a mmachi okpomọkụ nso mgbanwe na obere ntapu na batchwise. Dị ka nsogbu na-abawanye na viscosity na-abawanye, ma usoro pụtara na nrụgide n'elu 30,0 MPa (300 mmanya). Na omume, nke a na-akpata na-eleghara anya.

N'ihe na indexation

Dị na mba ISO ụkpụrụ, na viscosity nke mmiri (na ndị ọzọ dị mmiri mmiri) na-kwupụtara centistokes: CST (mm ² / s). Nha nke viscosity usoro mmanụ ga-rụrụ na okpomọkụ dị n'etiti 0 ° C, 40 ° C na 100 Celsius C. Na nke ọ bụla, na koodu akara mmanụ viscosity ga na-egosi onuogugu 40 Celsius C. Pụọ viscosity e nyere na 50 Celsius C. Marks, ọtụtụ na-eji na engineering hydraulics, nso si ISO VG 22 ISO VG 68.

Hydraulic mmanụ VG 22, VG 32, VG 46, VG 68, VG 100 na okpomọkụ nke 40 Celsius C nwere viscosities kwekọrọ ha labeling: 22, 32, 46, 68 na 100 CST. The kacha kinematic viscosity nke na-arụ ọrụ ọmụmụ na haịdrọlik systems idu ke nso nke 16 na 36 CST.

American Society of Automotive Engineers (Society of Automotive Engineers - SAE) eguzobewo àmà nke viscosities na kpọmkwem okpomọkụ na kwesịrị ekwesị codes kenyere ha. The nọmba esonụ akwụkwọ ozi W, - onye zuru ike viscosity ọnụọgụ μ na 0 ° F (-17.7 ° C), na ν na kinematic viscosity kpebisiri ike na 212 ° F (100 ° C). Nke a indexing banyere multigrade mmanụ na-eji na akpakanamde ụlọ ọrụ (nnyefe, moto, na na. D.).

Mmetụta nke viscosity na haịdrọlik ọrụ

Mkpebi siri ike nke viscosity nke ọmụmụ abụghị naanị na nkà mmụta sayensị na izi mmasị, ma na-eburu mkpa bara uru. The haịdrọlik oke mmiri bụghị naanị nyefee ike mgbapụta na haịdrọlik moto, ma ịtụ n'akụkụ nile na mmiri na-napụrụ okpomọkụ eme esemokwu ụzọ abụọ. Adịghị-ederịta akwụkwọ na-arụ ọrụ nke na-arụ ọrụ ọmụmụ viscosity nwere ike kpọrọ akpaghasị ịdị irè nke hydraulics.

The elu viscosity nke na-arụ ọrụ ọmụmụ (mmanụ nnọọ elu njupụta) na-eduga ná ndị na-esonụ mmetụta ọjọọ:

• The ụba eruba-eguzogide ndị haịdrọlik ọmụmụ-akpata oké nsogbu dobe na haịdrọlik usoro.
• Deceleration akara nke na-agba na n'ibu mezuo iwu nke actuators.
• Development of mgbapụta cavitation.
• Efu ma ọ bụ nnọọ ala ikuku ntọhapụ si haịdrọlik mmanụ tank.
• A kwesiri ngosi ọnwụ nke ike (mbenata arụmọrụ) nke hydraulics n'ihi na elu na-eri nke ike-esi merie esịtidem esemokwu nke ọmụmụ.
• Mụbara torque nke kasị haziri nke igwe kpatara amụba ibu na mgbapụta.
• The okpomọkụ ịrị elu nke haịdrọlik ọmụmụ N'ịbụ ụba esemokwu.

N'ihi ya, anụ ahụ pụtara nke ọnụọgụ nke viscosity bụ na ya mmetụta (ebughi) na mmiri na usoro maka ugbo ala, ígwè na akụrụngwa.

Loss nke haịdrọlik ike

The ala viscosity nke na-arụ ọrụ ọmụmụ (ala njupụta mmanụ) na-akpata na-esonụ mmetụta ọjọọ:

• Ụra volumetric arụmọrụ nke nfuli dị ka a N'ihi nke na-amụba esịtidem leakage.
• The abawanye na esịtidem leakage nke haịdrọlik mmiri ke ofụri haịdrọlik usoro - nfuli, valves, valvụ, haịdrọlik Motors.
• Mụbara wear nke pumping nkeji na nfuli jamming ruru ka ezughi oke haịdrọlik ọmụmụ viscosity mkpa maka lubrication nke rubbing akụkụ.

compressibility

Ọ bụla mmiri mmiri nrụgide abịakọrọ. Na-akwanyere mmanụ, coolants na lubricants eji na n'ibu injinịa hydraulics, empirically ọ chọpụtara na mkpakọ usoro inversely proportional na ọmụmụ uka na ya olu. The ego nke mkpakọ so ịnweta mmanụ ndị budata ala maka na mmiri na ọtụtụ ala maka sịntetik oke mmiri.

Na mfe ala nsogbu haịdrọlik ọmụmụ compressibility negligible mmetụta mbenata mbụ olu. Ma dị ike igwe na elu-mgbali haịdrọlik drive cylinders na nnukwu, nke a na-egosipụta onwe anya. Na haịdrọlik ịnweta mmanụ na a mgbali nke 10,0 MPa (100 mmanya), olu mbelata site 0,7%. Na nke a, a mgbanwe ke mkpakọ olu na a obere n'ókè-emetụta kinematic viscosity na ụdị mmanụ.

ọgwụgwụ

Mkpebi siri ike nke viscosity na-enye ohere ịkọ ọrụ ngwá na ígwè n'okpuru ọnọdụ dịgasị iche iche, na-ewere n'ime akaụntụ mgbanwe ọmụmụ ma ọ bụ gas mejupụtara, nrụgide, okpomọkụ. Ọzọkwa, akara nke na-egosi mkpa ka mmanụ na gas ụlọ ọrụ, utilities na ndị ọzọ ọrụ.