A COMPUTATIONAL FLUID DYNAMICS STUDY ON THE ACCURACY OF HEAT TRANSFER FROM A HORIZONTAL CYLINDER INTO QUIESCENT WATER

摘要

The discipline of prototyping and designing parts or components via direct numerical simulation offers engineers today a powerful tool in the understanding of physical problems. The manipulation and operation of numerical fields representing the conditions we wish to consider (for example by way of Newtonian fluid physics) provides insight and comparative confidence in decisions otherwise grounded on experience or experimental data. To gain this confidence however - that the model parameters and numerical solver are realistic - we must be stringent in their validation for any given problem. Illustrated in this paper is such a validation for free convective heat transfer (Nusselt number) from a horizontal cylinder into quiescent water. The fluid properties and free convective range of application reflect those occurring within Solar Domestic Hot Water (SDHW) storages with helically coiled Immersed Heat Exchangers (IHX). Once the solver parameters are approved as discussed here, models representing such SDHW storages may be parameterised for simulation under a suitable optimisation cost function.