Optimum Gap

Optimum Gap Size in Parallel Plate Flow Show that for the flow situation in Example 2.5, for a given net flow rate the optimum gap size for maximum pressure rise is... 

The increase in the drag-flow rate has a profound effect on performance. For a given flow rate q, the optimum gap size in SMP and JMP configurations can be obtained by differentiating Eqs. E6.10-2 and E6.10-4, respectively, with respect to H to give Hopt = 3q/Vo and Hopt = 3q/2Vo- Next we substitute these values in Eqs. E6.10-2 and E6.10-4 and find that the ratio of pressure rises is... 

Parallel-Plate Flow of Newtonian Fluids A Newtonian polymeric melt with viscosity 0.21b(S/in2 and density 481b/ft3, is pumped in a parallel-plate pump at steady state and isothermal conditions. The plates are 2 in wide, 20 in long, and 0.2 in apart. It is required to maintain a flow rate of 50 lb/h. (a) Calculate the velocity of the moving plate for a total pressure rise of 100 psi. (b) Calculate the optimum gap size for the maximum pressure rise, (c) Evaluate the power input for the parts (a) and (b). (d) What can you say about the isothermal assumption ... 

Figure 15. Optimum gap thickness between parallel Figure 16. Knudsen number for both sides of the heat...

By introducing the lateral structures to the air channel, the radiation heat transfer from the containment vessel is redistributed. The high heat transfer performance of the radiation-convection structure (hereafter called as radiation structure) effectively dissipate the heat received by radiation to the air and the overall heat transfer capacity can be increased depending on the channel system design. For the geometry of the air channel of black surface and fixed wall temperature condition, the overall heat transfer is predicted to increase up to 6 times than the heat transfer rate of the same gap size, and up to about two times than the rate at the optimum gap size without radiation structures... 

FIGURE 4.8 Scheme of ion packets A (solid circles) and B (blank circles) at the terminus of planar FAIMS (a) filtering A with optimum gap, (b) with narrower gaps, the resolution does not improve but A is partly lost, and (c) with wider gaps, the transmission of A does not increase but specificity drops. 

Fig. 15 shows a cell of ATR configuration [19] under electrochemical working conditions. The Weierstrass prism made of ZnSe (radius r = 5 mm, refractive index n = 2.6 at 647.1 nm excitation), which is longer by r/n than a hemispherical prism, is mounted in the bottom of the electrochemical cell. The experimental procedure is much more difficult than that of a normal SERS measurement. The single crystal electrode is carefully pressed against the prism with a micrometer and a spring, so that the optimum gap size d... 

The satrie effect occurred as tiie lattice pitch was reduced, but now the optimum water gap increased in value. Vfith reference to Fig. 2, for a 10-mm-thick wall, the optimum gap was >40 mm, while a 300-mm-thick wall yielded a minimum critical slab thickness for a water gap of about 30 mm. Furthermore, the uranium wall had to be at least 100 mm thick to be a better reflector than a 150-mm-thick wall reflector alone. At near-optimum lattice spacing, 40-mm waii was more reactive than water. Another feature of interest present in Fig. 2 is an apparent crossover in critical slab thickness in the 0- to 5-mm water gap range. This, implies. that in this tight-pitched undermoderated lattice a 10-mm wall held tight to the fuel cell boundary is a better reflector than a 20-mm-thick wall. On the other hand, near-optimum moderation at a 25.4-mm pitch, a wall is always a better reflector as its thickness is increased (see Fig. I). 

The optimum gap for most adhesive applications for engineering plastics is between 0.05 mm and 0.2 mm but sometimes a thicker joint with a flexible adhesive is the best solution, especially if there are high peel loads or the adhesive is acting primarily as a sealant and not as an adhesive (see Section 1.5). 

---