Numerical simulation of carbon dioxide dispersion from vertical vent release

Numerical simulation of carbon dioxide (CO2) dispersion from two vertical vent release tests, i.e. test 7 and test 11, recently commissioned by National Grid is studied. For Test 7, the vent pipe is 3 m high with 1 inch diameter while Test 11 is 3 m high and 2 inch in diameter. The flow is subjected to a transient wind condition where both the wind direction and magnitude are changing with time. The far field computations started from a source condition derived from curve fitting the near-field simulations conducted by Leeds University. For test 7 the output at one hundred and sixty eight-diameter (168-D) distance from the pipe exit was used whereas in test 11 the output at 255 vent exit diameters (255-D) downstream from the vent exit is used, at this point all the solid particles are vaporised and the mixture is in pure-gas phase. The CO2 release continues at a steady condition. For test 7 the maximum release velocity is about 80 m/s at 168-D distance and for case 11 the maximum release velocity is roughly 45 m/s at the vent centre line at 255-D distance from the vent exit.