Prandtl Number definition of Prandtl Number in the Free Online Encyclopedia.

Prandtl number [′pränt·əl ‚nəm·bər]

(fluid mechanics)

A dimensionless number used in the study of diffusion in flowing systems, equal to the kinematic viscosity divided by the molecular diffusivity. SymbolizedPr_m. Also known as Schmidt number 1 (N_Sc).

(thermodynamics)

A dimensionless number used in the study of forced and free convection, equal to the dynamic viscosity times the specific heat at constant pressure divided by the thermal conductivity. SymbolizedN_Pr.

Prandtl Number

one of the similarity criteria of thermal processes in liquids and gases; Pr = v/a = μc_p/λ, where v = μ /p is the coefficient of kinematic viscosity, μ is the coefficient of dynamic viscosity, p is the density, λ is the thermal conductivity, a - λ /pc_p is the thermal diffusivity, and c_p is the specific heat of the medium at constant pressure. Named after L. Prandtl, the Pr number is a physical characteristic of a medium and depends only on the thermodynamic state. For gases, it hardly varies with change in temperature; for diatomic gases, Pr ≈ 0,72, and for triatomic and polyatomic gases, Pr varies from about 0.75 to 1.0. In nonmetallic liquids, Pr varies more markedly with temperature for liquids of higher viscosity. For example, for water, Pr - 13.5 at 0°C, and Pr = 1.74 at 100°C; for transformer oil, Pr = 866 at 0°C and Pr - 43.9 at 100°C. For liquid metals, Pr ≪ 1 and changes little with temperature. For example, for sodium Pr - 0.0115 at 100°C and Pr = 0.0039 at 700°C.

The Prandtl number is related to the other similarity criteria —the Peclet number Pe and the Reynolds number Re —by the formula Pr = Pe/Re,

S. L. VISHNEVETSKII

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No references found	v] are not independent but are related via the Prandtl number Pr = [eta][C. Perturbations from ducts on the modes of acoustic thermometers by Gillis, K.A.; Lin, H.; Moldover, M.R. / Journal of Research of the National Institute of Standards and Technology 3]s) N = the numerical node above or north of node P n = the face between two control volumes expressed by node N and P; the number of nodes in solid flow direction NTU = number of transfer units Nu = Nusselt number Pe = Peclet number Pr = Prandtl number q = heat transfer rate, W Re = Reynolds number [R. Run-around energy recovery system for air-to-air applications using ... by Li, Meng; Simonson, Carey J.; Besant, Robert W.; Shang, Wei / HVAC & R Research 31 for vertical wall [DELTA]T = temperature difference between the wall and the adjacent fluid k = thermal conductivity, W/mK L = characteristic length, m Re = local Reynolds number Pr = Prandtl number, assumed Pr = 0. Verification of CFD modeling for smoke control using two compartment ... by Kang, Kai / ASHRAE Transactions	Prairie Village prairie wolf prairies praise Praise of Folly, The Prajadhipok Prajapati prajna Prajnaparamita Prakhov, Adrian Prakhov, Adrian Viktorovich Prakrit Prakrit Literature prakriti and purusha Prakrits pram Pramathanath Banerjea Prambanan Pramnek, Eduard Pramnek, Eduard Karlovich Pramoedya Ananta Toer Pranas Eidukevicius Pranas Vaicaitis Pranciškus Smuglevicius Pranciskus Smuglevicius Prandtl Number Prandtl, Ludwig Prandtl-Glauert rule Prandtl-Meyer flow prang Prangos Pranskus, Bronius Prapor Praporshchik Prasad, Jayashankar Prasad, Rajendra prasada Prasanta Chandra Mahalanobis prase prase opal praseodymium prasinite Prasinovolvocales Praskovia Andreevna Malinina Praskovia Fedorovna Sakharova Praskovia Frantsevna Kudelli Praskovia Ivanovna Vishniakova Praskovia Ivanovna Zhemchugova Praskovia Kudelli Praskovia Malinina Praskovia Nikitichna Angelina	Pranas Eidukevicius Pranas Vaicaitis Pranav Pranav Pranava Pranava pranavahasrotas Pranayama prance prance prance prance around pranced prancer prancers prances Pranciškus Smuglevicius prancing prancingly Pranciskus Smuglevicius Prandase Prandase prandial prandial prandially prandially Prandin Prandin Prandtl Prandtl Prandtl Number Prandtl numbers Prandtl, Ludwig Prandtl, Ludwig Prandtl-Glauert rule Prandtl-Meyer flow prang prang prang Prang Besar Prang Besar prang up pranged pranged pranging pranging Prangos Prangos prangs prangs Pranic Pranic prank prank prank Prank ad, liability, charges Prank call Prank Call Underground Prank phone call pranked Pranker

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v] are not independent but are related via the Prandtl number Pr = [eta][C.

Perturbations from ducts on the modes of acoustic thermometers by Gillis, K.A.; Lin, H.; Moldover, M.R. / Journal of Research of the National Institute of Standards and Technology

3]*s) N = the numerical node above or north of node P n = the face between two control volumes expressed by node N and P; the number of nodes in solid flow direction NTU = number of transfer units Nu = Nusselt number Pe = Peclet number Pr = Prandtl number q = heat transfer rate, W Re = Reynolds number [R.

Run-around energy recovery system for air-to-air applications using ... by Li, Meng; Simonson, Carey J.; Besant, Robert W.; Shang, Wei / HVAC & R Research

31 for vertical wall [DELTA]T = temperature difference between the wall and the adjacent fluid k = thermal conductivity, W/m*K L = characteristic length, m Re = local Reynolds number Pr = Prandtl number, assumed Pr = 0.

Verification of CFD modeling for smoke control using two compartment ... by Kang, Kai / ASHRAE Transactions