The shell-side method is based on the heat transfer j_i factor and the friction factor f_i from data on ideal tube banks and then correcting these values for the nonidealistics of the flow in a baffled exchanger. Pressure drop and heat transfer in ideal tube banks are described in Section 146 and Section 170, respectively. However, the development of the Delaware method was based on a specific set of ideal tube bank data with geometric similarity to shell-and-tube heat exchanger practices. For this reason it appears preferable to use the same set of graphs as a basis. These are presented in Figure 1, Figure 2, and Figure 3 as functions of the layout angles and pitch ratios L_tp/D_t, covering the industrial range of practical values.

Figure 1 Ideal tube bank j_i and f_i factors for 30° staggered layout [Re_s from Equation 251.25]

Figure 2 Ideal tube bank j_i and f_i factors for 45° staggered layout [Re_s from Equation 251.25]

Figure 3 Ideal tube bank j_i and f_i factors for 90° in-line layout [Re_s from Equation 251.25]

No attempt is made here to correlate the data, and the user is expected to read the corresponding value of j_i and f_i as functions of the Reynolds number Re_s, from the graphs. For possible computer application, however, a simple set of constants is given in Table 1 for a curve fit of the following form: