b'Industrial Machinery & Heavy Equipment | Engineer InnovationRun Primal Flow SolutionRun Adjoint Flow SolutionEvaluate Sensitivity of cost function to local cell porosityDeactivate (Solidify) unfavourable cellsExtract and Smooth SurfaceAnd this is exactly what the engineersspace. After the CFD has reached a at HP and Siemens saw. converged steady state solution for the given fluid domain, the adjoint function The evolution of the mighty duct was assessed. This is a quantitative Three things are required in order tomeasure for the effect of any local fluid redefine the impossible: firstvolume, i.e. computational cell, to the computational fluid dynamics; secondglobal cost function, in this case the topology optimization; and third,backpressure or the massflow rate additive manufacturing.through the air duct. In addition an equal mass flow split between the two So, the first step to improve the coolingprinter head channels is envisaged performance of the duct, was tothrough the cost function to ensure understand the status quo through CFDequal cooling performance of both the simulation. As the study immediatelycolor and the black head. The algorithm revealed the baseline design isthen automatically starts to convert characterized by a strong swirling flow.those local areas that have a negative The latter is caused by the fan that isimpact on the overall massflow rate and rotating at a few thousand rpm therebybalance by converting them into driving the air through the coolingimpermeable walls. After this step the system. Obviously, the tangentialCFD solver reassesses the flow for the swirling motion is of no benefit to themodified fluid domain and the loop desired directed air flow through thestarts over. duct. The secondary motion causes losses through undesired turbulenceBy these means the topology of the generation that is of no benefit to thefluid airflow path evolves; improving effective mass flow. And while manythe massflow rate with every iteration traditional engineers would potentially have come up with a static flow straightener or honeycomb pattern, the engineers at HP and Siemens took a completely new route.Rather than following the beaten track, the engineers embraced topology optimization embedded in the CFD tool. In a first step the design envelope was opened to the maximum available space that avoided interference with other parts of the carriage assembly. In a fully automatic iterative process the CFD simulation is used to assess the flow through the air duct, starting from the maximum available fluid volume 35'