The HXFLOW code predicts three dimensional distributions of all flow parameters on the shell side of the TEMA shell tube heat exchangers. HXFLOW can be used for design optimization@ comparative evaluation and performance predictions (including the study of detailed flow distributions to identify potential problem areas). To aid in tube vibration analysis@ an option exists to calculate and print tube gap velocities around the lengths of up to ten selected tubes. The HXFLOW code consists of three distinct modules: HXGEOM - the geometry pre-processor module into which all required geometrical data are read and processed; and HXSOLVER - the thermal-hydraulics module where all flow computations are made and CFD-VIEW ?C module for the graphical display of all results. The salient features of the code are summarized below : ? TEMA E@ F@ G@ J type Shell and Tube Heat Exchanger. ? 30 degree@ 45 degree@ 60 degree and 90 degree tube layout ? Single and Double segmental baffles ? Impingement Plate included in the model ? All data input using a Graphical User Interface@ where the user is guided by numerous on-screen sketches ? Capability to revise the grid density used for the solution process ? Both parallel-to and cross-flow velocity distribution along any tube in the tube bundle ? Graphical and numerical display of the results