With increasing depth of oilfield development, sublayers are becoming the main object of 0o9alkali-surfactant-polymer (ASP) flooding. Compared with major layers, sublayers differ in permeability, which may cause clogging of low-permeability layers when ASP solution containing polymer of the same molecular weight is injected into these layers. To solve this problem, injection allocators are widely used in oilfields. In this work, the jet nozzle channel was modeled using FLUENT 6.3 software. The ASP solution flowing through the jet nozzle channel in the injection allocator was simulated using a mathematical model based on the Navier-Stokes equation and renormalization group (RNG) turbulence and power-law fluid models. The effect of nozzle diameter on the distribution of differential pressure, velocity, average strain rate, turbulence power, and apparent viscosity of the flow were analyzed. It was found that with an increase in the nozzle diameter the differential pressure and velocity of the flow decrease before and after passing through the nozzle, whereas the average strain rate increases gradually. The simulation results can provide theoretical guidance for optimal design of the nozzle.