System dynamics model and startup behavior of loop heat pipe

The purpose of this article is to study the system dynamics model and startup behavior of loop heat pipe. A mathematical model in normal operation was derived from the experimental data. The model is presented as a matrix of second-order transfer functions. It is found that the system dynamics of a LHP is a variable-structure system that changes with operating conditions. The startup phenomena are studied experimentally. The startup phenomena of a LHP can be classified into four modes, based on the heat load: (1) failure mode: , (2) oscillating mode: , (3) overshoot mode: , and (4) normal mode: . For heat load , the overshoot phenomenon is observed. For , the oscillation phenomenon is observed. For , the startup failure is observed. All the startup behavior is of second- order.