Simulation of Fluid Flow in a Furnace Top Model of an Ethane Cracker

Induction fan failure on one of the furnaces at Ethylene Polyethylene Malaysia Sendarian Berhad (EPEMSB) in Terangganu was suspected to have been caused by vibration that resulted from a turbulent flow of the flue gas at the furnace exit. The damper flap at the stack inlet was believed to have had free and uncontrolled rotation due to the broken cotter pin, this was postulated to have led to the turbulence. The simulation of the flow was carried out to investigate this flow. The flapping angles of 900, 600, 300, and 00 were categorized in to four cases and simulated.
The simulation results showed that when all the flaps were at 90 degrees, the characteristics of the flow was not adversely changed, hence the flow at this flapping angle was laminar. At the flapping angle of 600, the change in characteristic of the flow was observed, the fluid velocity was seen to be increasing at the edges of the damper flap, the flow was visualised to be losing the laminar characteristic and gaining turbulent characteristic. At 300 flapping angle, the flow was visualised to be having a more turbulent characteristic. The fluid velocity was significantly increased at the edges of the flap at 300 and the flow characteristic was seen to be turbulent. The fluid flow was seen to be more turbulent at 00 due to larger area of separation of the flow. The sharp edged at ends of the flap were seen to be increasing the fluid velocity adversely.