# Liquid Water properties : correlations as a function of temperature

## Formula for calculating Density, viscosity, thermal conductivity of water

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1. Liquid Water density correlation : ρ=f(T)
2. Liquid water viscosity correlation : μ=f(T)
3. Liquid water thermal conductivity correlation : λ=f(T)
4. Water saturated vapor pressure : Psat=f(T)
5. Water properties : Free Excel calculation tool

Water critical parameters : [Dincer]

• Tc = 373.984 c
• Pc = 220.64 bar
• vc = 3.106 dm3/kg

Water triple point parameters : [Dincer]

• Tt = 0.01 c
• Pt = 611.732 Pa

## 1. Liquid Water density correlation : ρ=f(T)

How does the density of liquid water vary with temperature ? What is the equation to calculate the density of water ?

ρ=0.14395/(0.0112^[1+(1-T/649.727)^0.05107]) [DDB]

With

ρ = density (kg/m3)
T = temperature (K)
A = 0.14395
B = 0.0112
C = 649.727
D = 0.05107
Range of validity : [273 ; 648] K

## 2. Liquid water viscosity correlation : μ=f(T)

How does the viscosity of liquid water vary with temperature ? What is the equation to calculate the viscosity of water ?

μ = exp(-3.7188+578.919/(-137.546+T))

With

μ = viscosity (mPa.s)
T = temperature (K)
A = -3.7188
B = 578.919
C = -137.546
Range of validity : [273 ; 373] K

## 3. Liquid water thermal conductivity correlation : λ=f(T)

How does the thermal conductivity of liquid water vary with temperature ? What is the equation to calculate the thermal conductivity of water ?

λ'=-1.48445+4.12292*T'-1.63866*T'2 [NIST]

With

λ' = λ(T)/λ(298.15)
λ(298.15) = 0.6065 W.m-1.K-1
λ(T) = thermal conductivity of water at temperature T (W.m-1.K-1)
T' = T/298.15
T = temperature of water (K)
Range of validity : [274 ; 370] K

## 4. Water saturated vapor pressure : Psat=f(T)

How does the vapor pressure of water vary with temperature ? What is the equation to calculate the vapor pressure of water ?

log(Ps) = 8.07131 - 1730.63 / (233.426 + T)

With

Ps = Saturation pressure (mmHg) - note, to switch to Pa, multiply by 133.322 Pa/mmHg
T = temperature (°c)
A = 8.07131
B = 1730.63
C = 233.426
Range of validity : [1 ; 100] °c

Warning : all correlations proposed give an approximate value of the physical properties. No guarantee is given on the results.

## 5. Water properties : Free Excel calculation tool

You can access an Excel tool to apply the formula detailed above and make calculations. This tool contains :

• Water density calculator
• Water viscosity calculator
• Water thermal conductivity calculator
• Water vapor pressure calculator

Source
[Dincer] Drying Phenomena: Theory and Applications, First Edition. İbrahim Dinçer and Calin Zamfirescu, John Wiley & Sons (excerpt available online)
[NIST] Standard reference data for the thermal conductivity of water, Ramires et al, American Institute of Physics and American Chemical Society, 1995
[DDN] Dortmund Data Bank (online)