A numerical model has been developed for calculating x‐ray line emission from spherical plasma flows and has been applied to a laser‐heated, ablating aluminum target. The results are in good agreement with previous experimental work. The intensity ratios of the dominant lines are predicted in good agreement with experiment. A novel effect, not yet observed, is predicted in the interaction of nearby lines, here an H&agr;doublet: through Doppler shift caused by plasma flow one line absorbs the other. This line obscuring effect has potential applications to diagnosing details of ablative flows in x‐ray lasing and inertial confinement fusion experiments. The main features of the model are plasma parameters obtained through a Lagrangian hydrodynamics model, radiative transport by multienergy and multi‐impact parameter ray groups, and self‐consistent, time‐dependent computation of ion and ion energy‐level populations. Approximately 100 energy groups per line resolve line structure and show Doppler effects. The scalings involved in extending this work to other plasma conditions and materials are discussed.