Rectangular flat plates

Downcomers Rectangular flat plates bolted, welded or clamped to shell and trays inside of fractionation columns. Used to direct process liquid and to prevent by assing of vapor. 

Spirally wound cylindrical or rectangular flat plates Military, missiles etc. 

Flat-Plate Cell A cell fabricated with rectangular flat-plate electrodes (also called a Prismatic Cell). 

The major use for flat plate evaporators is to cool a solid product by conduction, the product being formed in rectangular packages and held close between a pair of adjacent plates. 

Peng XF, Wang BX, Peterson GP, Ma HB (1994b) Experimental investigation of heat transfer in flat plates with rectangular micro-channels. Int J Heat Mass Transfer 37 127-137... 

Equation (8.12) is a form of the convective dijfusion equation. More general forms can be found in any good textbook on transport phenomena, but Equation (8.12) is sufficient for many practical situations. It assumes constant diffusivity and constant density. It is written in cylindrical coordinates since we are primarily concerned with reactors that have circular cross sections, but Section 8.4 gives a rectangular-coordinate version applicable to flow between flat plates. 

We then wish to discover how tj depends on reaction and particle characteristics in order to use equation 8.5-5 as a rate law in operational terms. To do this, we first consider the relatively simple particle shape of a rectangular parallelepiped (flat plate) and simple kinetics. 

The average heat-transfer coefficient from horizontal flat plates is calculated with Eq. (7-25) and the constants given in Table 7-1. The characteristic dimension for use with these relations has traditionally [4] been taken as the length of a side for a square, the mean of the two dimensions for a rectangular surface, and 0.9d for a circular disk. References 52 and 53 indicate that better agreement with experimental data can be achieved by calculating the characteristic dimension with... 

A drawback to the rectangular cell design is that the hydrodynamic description of fluid flow is much more complicated than in the cylindrical cell. Though it is beyond the intent of this discussion to go into full detail, analytical solutions to the Navier-Stokes equation for steady laminar fluid flow have been derived that can be used for calculation of electro-osmosis at flat plates in the rectangular cell configuration where electro-osmosis may differ at the upper, lower, and side chamber walls [ 15). 

Peng, X.F., Wang, B.X., Peterson, G.P. and Ma, H.B., Experimental Investigation of Heat Transfer in Flat Plates with Rectangular Microchannels, Int. J. Heat Mass Transfer, 1995, 38(1), 127-137. 

Peng, X. and Wang, B., (1993), Forced convection and flow boiling heat transfer in flat plates with rectangular microchannels. International Journal of Heat and Mass Transfer 36,14, pp. 3421-3427. 

Statement of the problem. Thermal boundary layer. Let us consider heat transfer to a flat plate in a longitudinal translational flow of a viscous incompressible fluid with velocity U at high Reynolds numbers. We assume that the temperature on the plate surface and remote from it is equal to the constants Ts and 7], respectively. The origin of the rectangular coordinates X, Y is at the front edge of the plate, the X-axis is tangent, and the Y-axis is normal to the plate. 

One-dimensional charts find an important application in the solution of multidimensional problems. It can be shown (see, for example, Section 5.2 of Ret 1) that the dimensionless unsteady temperature of an infinitely long rod of rectangular cross section 21 X 2L may be expressed as the product of the dimensionless temperature of an infinite flat plate of thickness 21 times the dimensionless temperature of an infinite flat plate of thickness 2L,... 

Rectangular Isothermal Fins on Vertical Surfaces. Vertical rectangular fins, such as shown in Fig. 4.23a, are often used as heat sinks. If WIS > 5, Aihara [1] has shown that the heat transfer coefficient is essentially the same as for the parallel-plate channel (see the section on parallel isothermal plates). Also, as WIS - 0, the heat transfer should approach that for a vertical flat plate. Van De Pol and Tierney [270] proposed the following modification to the Elenbaas equation [88, 89] to fit the data of Welling and Wooldridge [283] in the range 0.6 < Ra < 100, Pr = 0.71,0.33 < WIS < 4.0, and 42 < HIS < 10.6 ... 

Although the two examples of laboratory equipment shown in Figs. 17.1 and 17.3 are for heat exchanger tubes other test sections may be used depending on the data desired. Square or rectangular flow sections may be employed where it is desired to remove a flat plate or coupon, for visual or other examination. Fig. 17.5 is an example [Patel 199 ]. Suitable studs may be incorporated into the wall of a tubular test section for the same purpose, but because of the curvature, the area of stud surface exposed to the flow is of necessity quite small. Fig. 17.6 is an example of a so-called Robbins device used in biofilm assessment. 

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