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A dimensionless number which is a ratio of kinematics viscosity to thermal diffusivity is known as?
where:
ν : kinematic viscosity, ν = μ / ρ, (SI units : m2/s)
α : thermal diffusivity, α = k / (ρcp), (SI units : m2/s)
μ : dynamic viscosity, (SI units : Pa s)
k: thermal conductivity, (SI units : W/(m K) )
cp : specific heat, (SI units : J/(kg K) )
ρ : density, (SI units : kg/m3 ).
answered by : eng_moom
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What are the transport properties of fluids?
Transport properties of fluids include viscosity, thermal conductivity, and diffusivity. Viscosity is a measure of a fluid's resistance to flow, thermal conductivity relates to the fluid's ability to conduct heat, and diffusivity describes how easily a substance can spread or diffuse within the fluid. These properties are important in various engineering applications, such as in fluid dynamics and heat transfer processes.
The ratio of thermal boundary layer thickness to the concentration boundary layer thickness is?
The ratio of thermal boundary layer thickness to the concentration boundary layer thickness is typically denoted as Prandtl Schmidt number (PrSc). It is defined as the ratio of thermal diffusivity to mass diffusivity of a fluid and represents the relative thicknesses of the thermal and concentration boundary layers in a flow field.
What is the Peclet number in simple terms?
The thermal Peclet number (Pet) is a measure of the relative importance of advective to conductive heat transport . Pet = (vl)/k where 'v' is the velocity at which the material is moving, 'l' a length scale and 'k' (kappa) the thermal diffusivity. In simpler words, Pet >>1 implies : advection dominates Pet <<1 implies : conduction dominates. [thermal diffusivity : can be thought of thermal inertia, a higher value means rapid movement/flow of heat through substance relative to its volumetric heat capacity or 'thermal bulk' is possible, therefore, when k is large, conduction dominates ] [advection : transportation of some qty via bulk flow of a fluid medium]
What is thermal viscosity?
It is of not much importance, but calculated as T.V. = 15 + 148(kinematic viscosity) It is used for less volatile fractions and important for illuminating oils. Ring no. is defined for illuminating oils which should be in a range of 60 to 130 Ring no. = (T.V/5)-10(46-API)
Why viscosity decreases with increase in temperature?
Temperature measures the speed of random thermal motion on the atomic and molecular level. When sub-microscopic particles are moving faster, the liquid as a whole will be more fluid and less viscous.
A dimensionless number which is a ratio of kinematics viscosity to thermal?
The ratio between the kinematic viscosity and the thermal diffusivity is called the Prandtl Number.
What are the transport properties of fluids?
Transport properties of fluids include viscosity, thermal conductivity, and diffusivity. Viscosity is a measure of a fluid's resistance to flow, thermal conductivity relates to the fluid's ability to conduct heat, and diffusivity describes how easily a substance can spread or diffuse within the fluid. These properties are important in various engineering applications, such as in fluid dynamics and heat transfer processes.
What is the physical significance of the thermal diffusivity and How is it defined and what?
Thermal diffusivity signifies the rate of heat transfer into the solid. If it is higher then less time is required for the heat to penetrate into the solid. it is th property of a solid. If we know the mass density,specific heat and thermal conductivity coefficient then we can determine its thermal diffusivity.
What is the thermal diffusivity of polypropylene?
Thermal diffusivity is the density divided by the specific heat of a substance. The TD of polypropylene is around 0.096 meters squared per second.
The ratio of thermal boundary layer thickness to the concentration boundary layer thickness is?
The ratio of thermal boundary layer thickness to the concentration boundary layer thickness is typically denoted as Prandtl Schmidt number (PrSc). It is defined as the ratio of thermal diffusivity to mass diffusivity of a fluid and represents the relative thicknesses of the thermal and concentration boundary layers in a flow field.
How to calculate thermal diffusivity and what factors should be considered in the calculation?
To calculate thermal diffusivity, divide the thermal conductivity of a material by its density and specific heat capacity. Factors to consider in the calculation include the material's composition, temperature, and physical state.
What is the difference between thermal diffusivity and thermal conductivity, and how do they affect the heat transfer properties of a material?
Thermal diffusivity measures how quickly heat can spread through a material, while thermal conductivity measures how well a material can conduct heat. A material with high thermal diffusivity can quickly distribute heat, while a material with high thermal conductivity can efficiently transfer heat. Both properties affect how a material responds to changes in temperature and how heat is transferred within it.
What is prandtl number and what is its significance?
Prandtl number is dimensionless number, denoted by Npr.Npr = Cp (viscosity)/(thermal conductivity) Cp - specific heat, J per ( Kg Kelvin) viscosity in poise (gm per( cm sec)) thermal conductivity in Watt per (meter kelvin) Prandtl number is important in heat transfer.
What is turbulent thermal diffusivity?
Turbulent thermal diffusivity is a measure of how quickly heat is dispersed in a turbulent fluid flow. It quantifies the rate at which temperature fluctuations spread through the fluid due to turbulence, and is important in predicting heat transfer in turbulent flows.
What has the author Anna Matvienko written?
Anna Matvienko has written: 'High-resolution measurements of thermal diffusivity of water-alcohol mixtures using a photopyroelectric thermal-wave cavity'
What has the author M di Marzo written?
M di Marzo has written: 'Transient cooling of a hot surface by droplets evaporation' -- subject(s): Experiments, Thermal analysis, Thermal diffusivity
What are the thermal parameters?
Thermal parameters are characteristics that describe how heat is transferred in a material or system. These parameters include thermal conductivity, heat capacity, thermal diffusivity, and thermal resistance. They are important in determining how a material or system responds to changes in temperature.
