The Basics-A Surge Tank

We begin with a formal statement of a conservation principle  

The rate of change of a quantity within a system equals the rate at which the quantity enters that system plus the rate at which that quantity is generated within the system minus the rate at which that quantity leaves the system and minus the rate at which that quantity is consumed within the system. 

The rate of accumulation equals input plus generation minus output minus consumption. 

The previous chapters on mass conservation dealt with systems at steady state, namely when accumulation equaled zero. We now generalize mass conservation to include accumulation we will discuss the generation and consumption terms later in the chapter. 

A surge tank is a simple system rich in transient phenomena and important engineering lessons. In its typical application, a surge tank may be used to average transients in a flow stream the flow into the tank may surge and ebb, but the flow out of the tank will be stable. We will use the production of citric acid as a case study in the use of surge 

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Marris, A.W. (1959). Large water-level displacements in the simple surge tank. Journal of Basic Engineering 81(12) 446-454. 

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