Nitrogen was injected into the loop heat pipe(LHP) as non-condensable gas(NCG)

and the operating performance of the LHP with NCG was studied for different NCG inventories

while heat loads were applied to the evaporator and heat sink temperatures. Under the adverse effects of NCG: the operating temperature of the evaporator was elevated by 2-10℃ depending on the heat load and heat sink temperature; such effect was notable for a smaller heat load(less than 60W) or at lower heat sink temperature(-5℃); the temperature controlling performance varied

leading to a corresponding failure range for the heat load; the startup temperature and super tup overshooting increased

and the startup time was prolonged; the temperature oscillation phenomenon and operating failure could be triggered. According to the temperature variations of the characteristic points along the loop

the physical mechanism of the effect of NCG on the operating performance was analyzed and discussed.