Tentative Design

Modification of some design parameters, figure 8.13(c), then rerating the design to meet thermal and hydraulic specifications and economic requirements. 

The stepwise procedure includes statements of some rules based on common practice. 

Specify the flow rates, terminal temperatures and physical properties. 

Choose the simplest combination of shell and tube passes or number of shells in series that will have a value of F above 0.8 or so. The basic shell is 1-2, one shell pass and two tube passes. 

Make an estimate of the overall heat transfer coefficient from Tables 8.4-8.7. 

Choose a tube length, normally 8,12,16, or 20 ft. The 8 ft long exchanger costs about 1.4 times as much as the 20 ft one per unit of surface. 

---

Fig. 28.16. Tentative design for o self-sprung wheel. The spokes and the rim both deflect. The design ensures that the sum of the deflections is constant.

Rating of the tentative design, Figure 8.13(b), which means evaluating the performance with the best correlations and calculation methods that are feasible. 

These are tentative designations specified by the American Society For Testing Materials. 

The FRI data for dualflow trays have been used to form a tentative design method (Garcia and Fair, 2002). Data for Turbogrid trays have been included in the model. A generalized chart for predicting allowable vapor velocity, similar to that for cross flow trays given in Fig. 13.32(b), is included. 

Suppose now that the designer has developed a tentative design for the vessel, which includes the number of layers, material specifications for each layer, and the thickness of each layer, as well as the determination of the installation temperature, cure and operating conditions, and the maximum and minimum ambient temperatures that will be encountered both during operation and when idle. These operating and cure conditions to be specified are inside temperature and pressure, ambient temperature, and inside and outside heat transfer coefficient. 

Advantages 199 Tube Side or Shell Side 199 Design of a Heat Exchanger 199 Tentative Design 200... 

Zhang K, McClure JA, Elsayed S, Conly JM (2009) Novel staphylococcal cassette chromosome mec type, tentatively designated type VIII, harboring class A tnec and type 4 ccr gene complexes in a Canadian epidemic strain of methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother 53 531-540... 

Only the tubes inside the reactor and through the bottom plug are being provided in present construction. However, a tentative design for the entire system proposed by OBNL is outlined in Appendix 10. 

M and N proteins of Synechococcus are homologous to chloroplast ORF34 and ORF43, respectively [7]. Hence, we tentatively designate these ORFs, psbM and psbN. although their products have not yet been confirmed in plants. 

The third step is again preceded by a decision is the mix design to be performed with or without application of an optimization approach In both cases, iterative procedure is necessary. However, it is believed that the left-hand path in Figure 12.1 is shorter and leads to better results, because objective indications from the optimization approach are used. The tentative design may in many cases be started with a very distant solution from the final one. The end of the design is presented in the form of a Ust of components with their volume or mass fractions, computed for one cubic meter or for one batch. 

Some tentative design characteristics of the KAMADO are given in Table XIII-1. 

---