Flow models output characteristics

Models such as the MFA interact well with a mass-integration framework. The MFA model provides the data needed for mass integration (e.g., flows, concentrations of sources and sinks, impact of a change in input on the output characteristics, etc.). 

The flow rate at the applicator nozzle can be controlled by varying the rate at which the transfer pump propels the adhesive along the delivery pipe, assuming a constant delivery orifice. While this provides some control compared to the constant pressure/constant orifice methods, the response time to fluctuating needs is slow and there is considerable hysteresis in the system which provides poor overall control over the output rate. It is possible to model the characteristics of such a system and to include this information into the control circuitry. Nevertheless the overall control is still poor it is also greatly influenced by the compressibility of the material being dispensed and the expansion characteristics of the delivery pipework. 

VFO works well in gas turbines. In a nine-month test program, the combustion properties of VFO were studied in a combustion test module. A gas turbine was also operated on VFO. The tests were conducted to study the combustion characteristics of VFO, the erosive and corrosive effects of VFO, and the operation of a gas turbine on VFO. The combustion tests were conducted on a combustion test module built from a GE Frame 5 combustion can and liner. The gas turbine tests were conducted on a Ford model 707 industrial gas turbine. Both the combustion module and gas turbine were used in the erosion and corrosion evaluation. The combustion tests showed the VFO to match natural gas in flame patterns, temperature profile, and flame color. The operation of the gas turbine revealed that the gas turbine not only operated well on VFO, but its performance was improved. The turbine inlet temperature was lower at a given output with VFO than with either natural gas or diesel fuel. This phenomenon is due to the increase in exhaust mass flow provided by the addition of steam in the diesel for the vaporization process. Following the tests, a thorough inspection was made of materials in the combustion module and on the gas turbine, which came into contact with the vaporized fuel or with the combustion gas. The inspection revealed no harmful effects on any of the components due to the use of VFO. 

We have previously discussed outputs and inputs for process models we now introduce more precise working definitions. The word output generally refers to a controlled variable in a process, a process variable to be maintained at a desired value (set point). For example, the output from the stirred blending tank just discussed is the mass fraction x of the effluent stream. The word input refers to any variable that influences the process output, such as the flow rate of the stream flowing into the stirred blending tank. The characteristic feature of all inputs, whether they are disturbance variables or manipulated variables, is that they influence the output variables that we wish to control. 

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