Minimum structural change rearrangement

The structure of this formula can quickly be related to the thin-walled pressure vessel cylinder equation. Using the equation that calculates the stress at the center of the vessel wall, ux = P R + 0.5t)/t, and rearranging to solve for the thickness, results m. t = PR/ ux — 0.5P. The addition of the weld joint efficiency, E, and changing the coefficient before P to 0.6 results in the ASME code formula, t = PR/ SE — 0.6P), which they feel best represents the minimum wall thickness required to contain an internal pressure, P, in a cylindrical vessel having a radius, R, and made of a material with an allowable stress, S. 

This well-known relation is illustrated in Figure 4.1. In practice, the transition between the fixed and fluidized states involves some particle rearrangement, with the breakdown of bridging structures, which are inherent in the initial packing and subsequent defluidization operations rather than an abrupt change in slope at the minimum fluidization velocity C/ /, a more gradual approach to the constant APb is observed in practice, often with some overshoot in the transition region. 

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