Wind tunnel experiments have been performed to simulate the dispersion of hot exhaust gases from power generation plants on a notional model of an offshore platform. The experiments were stimulated by a growing concern for the effects of high temperatures in the vicinity of helidecks, heating and ventilation systems, gas turbine intakes, sensitive structural members and working areas in general.

The aim of the work has been to provide general guidance on the levels of temperature and the nature of their fluctuations, for a number of simple platform exhaust configurations. The results provided are not a substitute for a detailed study of a particular platform's problems, but should assist the designer in judging, at an early stage, where difficulties might be encountered.

The results show the development of plumes and the associated decay of temperature downstream when elevated outlets are employed or when the exhaust gases are released near the platform. Encouraging results have been found for long downward outlets, though in practice, there is some evidence that directing the efflux downward through short ducts can be unsatisfactory.

Irrespective of orientation, jets of exhaust produce an intermittent turbulent plume in which the temperature can fluctuate greatly. As a result short localised bursts of hot gas can occur, in which the excess temperature may be two or three times the average value for say a second or so. This unsteady aspect of the temperature field emphasises the need for designers to consider the dynamic characteristics of any system thought to be vulnerable to temperature rise.