The cavitation phenomenon can occur in many devices such as pumps, pressure-reducing valves and orifices. In the present work, we study the cavitating flow through a circular orifice using numerical tool and an improved cavitation model. In this model, we derive the phase-change rate expressions from a reduced form of the Rayleigh-Plesset equation for bubble dynamics, which depends on local flow conditions (such as pressure, velocities and turbulence intensities) and the fluid properties. We use the finite volume method to discretize the equations and SIMPLEC algorithm to link the pressure and velocity fields. The convection fluxes in all transport equations are modeled using an upwind scheme. We consider the standard k-ε model to treat the turbulence effects. Computations are performed at fixed inlet and outlet pressures. The current results are compared with the other published experimental and numerical works performing acceptable accuracies. Contrary to the past investigations, the current study provides more comprehensive details of pressure and water vapor volume fraction. It will be shown that increasing the inlet pressure affects the cavitation length and volume vapor fraction distribution considerably. We also study the effects of fluid temperature and the pressure outlet separately. The results show that as the temperature increases, the cavitation size increases. There is a delay in inception of cavitation as the pressure outlet increases.