The article describes the original state of the discharge valve design in terms of geometry and flow conditions. Through the simulations performed, it shows in detail the velocity and pressure fields in the valve in individual time steps of the liquid discharge process. By combining numerical and analytical calculations, it determines the total liquid flow through the valve during a specified time interval, while based on the knowledge gained, it suggests changes to the valve geometry to optimize the liquid flow. Key geometry modifications include the elimination of various sharp edges of individual elements of the original design but also limiting the maximum valve extension distance in the open mode. Performing the calculation for the optimized shape demonstrated a significant improvement in the valve flow properties compared to the original variant by 49% during the first second, or 52% during the first 2 seconds after opening the valve.