The open source software OpenFOAM was applied to simulate the single rising bubble's behavior.At first

the rising speed and shape of the bubble in references were simulated.The results fit well with the experimental data

thus the accuracy of the calculation model was verified.Variation of the rising speed

pressure and aspect ratio of the bubble with different initial diameters against the time

and effect of the Bo number and Mo number on bubble shape were systematically investigated by employing this validated model.The results showed that

the bubble's speed would increase for a while during its rising

and eventually reached a steady value with slight fluctuation.The larger the bubble's initial size

the higher the final speed of itself.Pressure inside the bubble increased to the maximum rapidly at first

and then decreased with the time.At the same moment

the bubble with larger size had higher pressure inside.When the bubble's diameter tended to a certain value

the final aspect ratio turned to constant.When the bubble's Bo number was small(at or lower than O(0)magnitude)or the Mo number was large(at(O(8)magnitude)

the bubble was spheric and nearly had no deformation.Enlarging the Bo number or decreasing the Mo number

the bubble's shape gradually changed.