Backmix Flow BMF

2 TYPES OF IDEAL FLOW, CLOSED AND OPEN VESSELS 13.2.1 Backmix Flow (BMF) 

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The fluid inside each vessel is perfectly mixed (backmix flow, BMF), and hence its properties are uniform at any time, because of efficient stirring. 

Ideal flow is introduced in Chapter 2 in connection with the investigation of kinetics in certain types of ideal reactor models, and in Chapter 11 in connection with chemical reactors as a contrast to nonideal flow. As its name implies, ideal flow is a model of flow which, in one of its various forms, may be closely approached, but is not actually achieved. In Chapter 2, three forms are described backmix flow (BMF), plug flow (PF), and laminar flow (LF). 

Backmix flow (BMF) is the flow model for a CSTR, and is described in Section 2.3.1. BMF implies perfect mixing and, hence, uniform fluid properties throughout the vessel. It also implies a continuous distribution of residence times. The stepwise or discontinuous change in properties across the point of entry, and the continuity of property behavior across the exit are illustrated in Figure 2.3. 

Open vessel the fluid may have any degree of backmixing at the inlet and outlet that is, the flow at these points may be anywhere between the extremes of PF (no backmixing) and BMF (complete backmixing). 

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