Dear Muhammad Yousaf,

You can use the following function(Kays et al., 2005):

k_water=-8.354e-6T^2+6.53e-3T-0.5981,

Regards,

P.S.

W. Kays, M. Crawford, B. Weigand, Convective Heat and Mass Transfer, fourth ed., McGraw-Hill, Singapore, 2005.

Water does have thermal conductivity, however, it behaves in a convective manner the moment there are temperature differences in a volume. In practise, thermal conductivity will define how quickly heat is transferred to the liquid, adjacent to the heat source, but convection will dominate what happens to the heat next.

There are many sites citing the properties, e.g. http://www.engineeringtoolbox.com/water-properties-d_1508.html. You can derive the relationship from there.

Dear Muhammad, on the page 5 ( eq. 12) of this paper you would find demanded correlation :

V. Bianco et al. / Applied Thermal Engineering 29 (2009) 3632–3642

Good luck

Dear Muhammad Yousaf,

You can use the following function(Kays et al., 2005):

k_water=-8.354e-6T^2+6.53e-3T-0.5981,

Regards,

P.S.

W. Kays, M. Crawford, B. Weigand, Convective Heat and Mass Transfer, fourth ed., McGraw-Hill, Singapore, 2005.

@Amin, Thanks

Dear Mohammad,

You can find the thermal conductivity of the water as a function of temperature in the attached paper.

@Amin Ebrahimi, i used the same equation but did not work

for T=90oC Kwater=-139 for if T=363.15K K=-2.6134*10^3. K should be 0.67570W/m.K

Can you please tell why the equation is not working? where did i wrong?

John, i found it thanks. 

k water = 0.5706+1.756*10^-3 * T -6.46*10^-6* T^2 (Wiley online lib. Appendix C, Properties of Water)

this equations gives the thermal conductivity of water @ R^2 = 1.

https://www.nist.gov/sites/default/files/documents/srd/jpcrd493.pdf

https://www.nuclear-power.net/nuclear-engineering/heat-transfer/thermal-conduction/thermal-conductivity/thermal-conductivity-of-water-and-steam/