Competitive global markets are increasing the commercial pressure on manufacturing companies to develop better products in less time. To meet these demands, the appliance manufacturer, Fisher & Paykel, has considered the use of computer simulation of fluid flows to assist in product design. This technology, known as Computational Fluid Dynamics (CFD), has the potential to provide rewarding insight into the behaviour of designs involving fluids. However, the investment in CFD is not without risk. This thesis investigates the use of CFD in oven design expressly to evaluate the numerical accuracy and suitability of CFD in the context of oven product development. CFD was applied to four cases related to oven design, along with detailed experimental investigations, and resulted in a number of relevant findings. In a study of an impinging jet, the SST turbulence model was found to produce better results than the k-ε turbulence model. Measurements indicated that the flow was unsteady, but CFD struggled to reproduce this behaviour. The synergy between experimental and numerical techniques was highlighted in the simulation of a two-pane oven door, and resulted in temperatures on outer surface of the door predicted by CFD to within 2% of measured values. In the third study, a CFD simulation of a tangential fan failed to deliver acceptable steady-state results, however a transient simulation showed promise. The final case examined the flows through the door and cooling circuit of the Titan oven. Velocities predicted by CFD compared well against measurements in some regions, such as the potential core of the jet at the outlet vent, but other regions, such as entrained air, were poor. Temperatures were predicted to within an average of 2% of measured values. It is found that limited accuracy does not necessarily prevent CFD from delivering engineering value to the product development process. The engineering value delivered by CFD is instead more likely to be limited by the abilities of the user. Incompatibilities between CFD and the product development process can reduce the potential value of CFD but the effects can be minimised by appropriate management action. The benefits of CFD are therefore found to be sufficient to merit its use in the product development process, provided its integration into the organisation is managed effectively and the tool is used with discernment. Recommendations for achieving this are provided.