Heat exchanger modelling

Figure 52. TRNSYS model with Excel data reader, simple tank (pipe volume) DST borehole heat exchanger model, and error function...

In formatting the inequalities g and equations h, you will find that the so-called open-equation representation is preferred to the closed-equation representation. One of the simplest examples is a heat exchanger model (the closed-equation format) ... 

Solution of Packed Bed Heat-Exchanger Models by Orthogonal Collocation Using Piecewise Cubic Hermite Functions... 

The heater, cooler, and heat exchanger models allow the design engineer to enter estimates of film transfer coefficients, and hence calculate the exchanger area. As with distillation columns, the designer must remember to add a design factor to the sizes predicted by the model. Design factors are discussed in Section 1.7. 

Figure 4.29. Feed-effluent heat exchange model for Example 4.5.

Smith, A. J. (1984). Solving distributed heat-exchanger models by the method of characteristics, Trans. Inst. M. C., 6, No. 2, 83-88. 

The heat exchanger models in Simprosys are based on Knudsen et al. (1997), Richard et al. (1997), Walas (1990), Kuppan (2000), Kakac and Liu (2002), McCabe et al. (2(XX)), and Minton and Morrison (2003). The cyclone models are based on Pell and Dunson (1997), Zenz (1999), and Reynolds et al. (2002). The electrostatic precipitator model is based on Pell and Dunson (1997) and Reynolds et al. (2002). The wet scrubber model is based on Pell and Dunson (1997) and Schifftner and Hesketh (1983). All the other unit operation models of Simprosys are based on Perry (1997). For more general information about Simprosys, please refer to Gong and Mujumdar (2008). For detailed information about the burner unit operation, please refer to Gong and Mujumdar (2014). 

Owing to the comparatively large share of wall material, longitudinal heat conduction in the channel walls has to be taken into account when attempting to formulate a heat-exchanger model. In contrast, the models for conventional heat exchangers usually account for transversal heat transfer from one fluid to another... 

Install the Pre-Heater unit, using the Heat-exchanger model, with Feed and Pre-Heat as the tube-side inlet and outlet streams, and with R-Prodl and R-Prod2 as the shell-side inlet and outlet streams. Click Parameter at the left side of the window. Specify Delta p as 0 for both tube side and shell side. Choose Weighted Exehanger as Model. Close the window. 

When streams on both sides of a heat exchanger are considered in process design with a simulation program, a two-sided heat exchanger model is used. The model applies Eq. (13.1) to each side under conditions of equal heat transfer rates, assuming that the exchanger is well insulated such that heat losses are negligible. Thus, all of the heat released by one side is taken up by the other side. In addition, a transport equation is applied ... 

Equation (4.19) is the heat exchanger model derived in Example 3.5. 

There is one heat-exchanger model in the standard model that considers heat-exchanger dynamics, but is only available for the reboUer. The Dynamic model uses the holdup of the... 

The standard basic RadFrac model in Aspen simulations does not accurately predict the rapid pressure changes during emergency situations because the default heat-exchanger models do not account for heat-exchanger dynamics (condenser and reboiler). Simulations can be developed that include external heat exchangers whose dynamics can be incorporated with the model of the column vessel. 

Kim, G-Y, Mayor, JR, Ni, J. Parametric study of microreactor design for water gas shift reactor using an integrated reaction and heat exchange model. Chem. Eng. J. 2005 110 1-10. 

Pump and tank model Compressor model Heat exchanger model Cooling tower model Boiler model Furnace model... 

Pump and tank model Compressor model Heat exchanger model Cooling-tower model Steam-generation model Furnace model Distillation model Reaction model Separation model Absorption and stripping model Combination of the preceding models... 

Figure 17-7 shows the basic components of a heat exchanger model. A variety of troubleshooting scenarios can be applied to this simple model. Variations depend on the instructor s experience and questions generated by the students. 

In Figure 1 are shown the closed loop results for the proposed measurement-driven calorimetric controller (Eq. 46) (continuous plots) and for its exact model-based nonlinear SF counterpart (discontinuous plots) (Eq. 43). As it can be seen, the difference in behavior between the two controllers is almost imperceptible. The small differences are due to the estimation error dynamics. In other words, as expected from the theoretical developments, the calorimetric controller basically recovers the behavior of its exact model-based nonlinear SF controller (Eq. 43) counterpart, without needing the kinetics and heat exchange models. As... 

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