The exit temperature profile of an LPP combustor has been studied experimentally and numerically in this paper. The combustor has been designed to incorporate three sectors within which the flow, spray and exit temperature characteristics have been investigated by PIV, PLIF and thermocouple measurements. The numerical simulation has been performed by the RANS method. Turbulences have been modeled by the realizable k-ϵ method and the combustion chemistry described by the FGM model. Liquid droplets have been tracked in the Lagrangian framework. The discrete effusing cooling flows on the flame tube have been modeled by source term method. Compared to the experimental results, the proposed CFD method predicted well the flow structure, spray distribution as well as the exit temperature of the tri-sector combustor and it has been employed to study the effect of main swirler designs on the exit temperature. Four main swirlers with different swirl numbers and axial velocities have been calculated and results have shown that the associated structure of the central recirculation zone had dominant impact on the exit temperature pattern. It has been finally proposed that designing the main swirler to generate a wide yet short recirculation zone could improve both the pattern and profile factor for the given LPP combustor.