This paper developed a three-dimensional computational fluid dynamics model of the supercritical water gasification (SCWG) process of glycerol. The detailed flow field, temperature field and chemical species distributions inside the reactor were revealed, and the effects of the operating parameters on the results in the SCWG of glycerol were investigated. The reasons for incomplete gasification were discussed, and relevant possible improvements were proposed. (1) The residence time is not long enough for the complete gasification; therefore, the optimal length of the tubular reactor was obtained under different operating conditions. (2) A side-reaction region was formed near the feeding inlet and methods to reduce the volume of the side-reaction region were investigated. A high preheated water temperature and a 135 degrees feeding angle were proved to obviously avoid side-reaction. A multi-injection feeding method can also suppress the side-reaction, but the carbon gasification efficiency decreased. (C) 2015 Elsevier B.V. All rights reserved.