Techniques for calibrating a high fidelity (HF) model of molten droplet coalescence are disclosed. An example method includes selecting initial HF parameter values for the HF model. The method also includes iteratively refining the HF parameter values until the HF model converges with experimental data. At each iteration, the HF parameter values are applied to the HF model and a plurality of simulations are run using the HF model to generate the simulated numerical data. For each simulation, a Reduced Order Model (ROM) is fitted to the simulated numerical data to generate ROM parameter values for ROM parameters of the ROM. Correlations between the ROM parameters and the HF parameters are identified to narrow the search space to be searched in a next iteration.