Ground influence on high-pressure methane jets: Practical tools for risk assessment

Unignited high-pressure methane jet impacting a cylindrical obstacle: An assessment tool for consequences analysis

“…The variation of all these parameters has led to investigate several cases, defined accordingly to values reported in Table 3. In agreement with previous works (Colombini et al, 2019a;Colombini et al, 2019b;Colombini et al, 2020a;Colombini et al, 2020b;Colombini et al, 2021a), the axial maximum extent (ME) of the cloud was recorded to quantify the obstacle effect on the methane jet. Considering the horizontal obstacle case, the results obtained are reported in the last three columns of Table 3.…”

“…• With respect to what found for other kind of obstacles when impinged by a high-pressure jet (Colombini et al, 2020a, Colombini et al, 2020bColombini et al, 2021a;Colombini et al, 2021b;Colombini et al, 2021c), the cylindrical obstacle (be it oriented horizontally or vertically) has the effect of decreasing the jet maximum extent instead of increasing it; at most, the impinging jet results to have similar length of the free jet case;…”

“…With this approach, on one hand we avoided a useless dense mesh in correspondence of the domain outskirts; on the other hand, we obtained a high-degree refinement within the volume surrounding the jet axis. More details regarding this mesh strategy are reported elsewhere (Colombini et al, 2020a, Colombini et al, 2021c. A fully unstructured tetrahedral grid was obtained for all the considered configurations.…”

“…where 𝑐𝑐̅ is the methane concentration of interest in air and k is the axial decay constant (equal to 4.4, as suggested by Birch et al (1984)). Note that, the reliability of Chen and Rodi (1980) model is discussed elsewhere (Colombini et al, 2020a, Colombini et al, 2021a, Colombini et al, 2021c 3. Coupling the models of Chen and Rodi (1980)…”

Unignited High-Pressure Methane Jet Impinging a Pipe Rack: Practical Tools for Risk Assessment

“…Therefore, to predict how severe may be the consequences of a FF, the extension of the unignited flammable cloud needs to be estimated (Souza et al, 2019b). Commonly, in the risk analysis framework, for the case of a leakage of a flammable substance such evaluation traduces in the prediction of the Maximum axially-oriented Extent (ME) of the cloud (Tchouvelev et al, 2007;Houf et al, 2010;Pontiggia et al, 2014;Colombini et al, 2020a).…”