Experimental evaluation of subsonic-horizontal jet flames: Impact of practical crack shapes

Accidental leakage of flammable gas with momentum emanating from pipeline cracks when met with an ignition can bring about turbulent diffusion flames known as jet fires. The jet fire geometry is a vital parameter in fire safety calculations and in the design of safe process facilities. The previous research confirms that the jet geometry is influenced by the shape of such cracks (shape of the source). This paper deals with the experimental evaluation of the geometry of a horizontally oriented, turbulent jet flame with 13 source shapes ranging from the conventional ones to the complex ones, such as a branched crack. The phenomenological constant in the implicit correlation suggested by Quintiere and Grove is correlated to the normalized form of hydraulic diameter. Based on this, a modified explicit correlation is proposed. The sensitivity of flame height and the transition behaviour of flame heights are represented with the modified heat release rate in terms of perimeter (Q*p,) and critical values of Q*p. The present study makes observations and offers conclusions in terms of hydraulic diameter and perimeter, which circumvent the dependency of the jet flame geometrical characteristics on source shape.