A numerical study has been done to investigate natural convection flow in a partially open square cavity, which consists of multiple heat sources at the bottom. In electronic systems generally, the chips are embedded in circuit boards, which are the primary sources of heat generation. Along with the increase in electronic miniaturization, the electronic density is also increasing. So an investigation has been carried out to know the effect of the presence of a number of heat sources on the heat transfer rate. Steady-state natural convection heat transfer in a partially open enclosure is studied numerically by solving the equation of momentum and energy using the algebraic multigrid solver of FLUENT 15. The optimum heat transfer rate and average Nusselt number are governed by the dimensionless spacing, height of the heat source, and the opening size. It is concluded that the average Nusselt number is influenced by the change in Rayleigh number, the dimensionless spacing between the heat source, opening size.