The present thesis is the result of a three year research study on the developing and experimental validation of a numerical model for the thermal-hydraulic simulation of Closed Loop Pulsating Heat Pipes. The project has been carried out in the framework of the PRIN-2009 and put the basis for a fruitful collaboration between the University of Bergamo and the Indian Institute of Technology Kanpur (IITK, India). The first two years were mainly devoted to improve the theoretical model and to the subsequent implementation of new subroutines. During this first stage the model has been validated by means of experimental data available from the literature. In the last year an actual CLPHP test-rig has been designed, built and tested. The outcome of the proprietor experimental apparatus provided new data on the heat transfer capability of two phase flows in mini-channels and allowed to perform a more accurate quantitative comparison with the simulation results. Although the final version of the numerical model is able to satisfactorily reproduce many trends of actual PHP devices, further work is needed in order to understand some open issues related to the physics and to release a reliable software tool for the PHP design.