As the concern about environmental problems and overuse of fossil fuels increases, alternative fuels with low heating values have been gaining much attention. Combusting the fuels requires modified gas turbines in terms of design and operation parameters. In this study, we aim to find appropriate parameters for designing gas turbines that combust low-heating-value fuels (LHVFs) through computer simulation. The results indicate that the jet penetration depth, inlet gas coefficient, and jet flow direction in the wall jet inlet require adjustment in the combustor design. The simulation shows that a pair of small vortices form in the front of the dome region. The length of the recirculation flow is only 0.18D (D: inlet diameter of the combustor), which does not significantly affect the flame-holding ability. The results also reveal that the strength and size of the recirculation flow in the primary combustion zone must be increased as the center of the flow moves to the liner wall. The high-temperature zone must also be close to the liner, and the center of the recirculation flow must be close to the liner wall. As a result, the combustion efficiency of LHVFs in the newly designed combustor is improved by 47% from that of a conventional combustor. The results of this study are expected to lead to new innovative designs of combustors of LHVFs that save resources and reduce pollutant emission.