I am planning to run a numerical simulation which involves melting of phase change material. I need thermal conductivity data at certain points to input the numerical model to get more exact results.
All the thermal conductivity of materials are measured at certain temperature using either cryogenics or heating stage. You can use LFA, which is a commercial product for measuring thermal conductivity of bulk materials.
It really depends on how large is your sample and whether your sample is bulk material or thin film material. If it is bulk sample, probably using LFA or the equivalent method is simplest to do.
202. E. Litovsky, V. Issoupov, S. Horodetsky, J. Kleiman, Express Methods for Determination of Apparent and True Thermophysical Properties of Materials within a Temperature Range of – 150 °C ... 1800 °C, Proceedings of the 31st International Thermal Conductivity Conference and the 19th International Thermal Expansion Symposium, May 2013, DEStech Pupbl.