A model of heat and mass transfer inside a pressure cooker

A model has been developed to describe steam cooking in a pressure cooker. The physical and thermal characteristics of commercial pressure cookers and of the food cooked in them, heat and mass transfer laws and various phenomena (conduction in solids, liquid and gas free convection, undercooled and emitted steam boiling, condensation and also valve opening laws) were all taken into account. Gas and water were considered to be two homogeneous fluid compartments. The hot plate was also modelled. This model enabled the prediction of heat and mass fluxes and pressures, the composition of gas, the temperature in the fluid compartment and temperature pattern in food under non-steady conditions during the three periods of cooking (pressure increase, pressure regulation and pressure decrease). The model was validated experimentally using an instrumented device containing a model foodstuff (PTFE cube). The fluxes generated by the model enabled the description of pressure and temperature increases, and allowed us to suggest better methods for energy-saving and rapid steam cooking.

► We model pressure cooker from lid closing to lid opening under unsteady conditions. ► Heat and mass transfer, water phase transitions and valve opening laws are used. ► Fluxes, pressure, gas composition, fluids and food temperatures are well predicted. ► We suggest better methods for energy-saving and rapid steam cooking.