Mr. Alatyar, the plate-frame exchanger as it obtains today is the culmination of its development for over a century. The use of pin fins as spacers has been tried before. But it is not a match to corrugated surfaces. In addition to thermal inferiority of pin fin spacers (heat transfer per unit of pumping power, for example), it is also mechanically inferior. The attaching of fins to the base surface will be more expensive, and difficult, to manufacture. The fins are short, hence their fin effectiveness (not the same as heat exchanger effectiveness) will be close to unity. Still they are secondary surfaces, while the corrugated surface is entirely primary surface. Finally, the corrugations increase the moment of inertia of the plate so that even sheets as thin as 0.5 mm can withstand impressive pressure differences. The number of support points (contact points) between a pair of plates cannot be matched by pin fins. If you try for the same number of contact points, the pressure drop will be enormous because of the bluff shape of the spacer fins.

To corrugate the plates requires heavy presses but the pressing of each plate takes just seconds and no heat! Imagine the pin fin joining process.

Contrary to earlier assumptions, there are few regions of flow stagnation in the plate space. Look for figures in the literature that show that the zig-zag flow occurs predominantly along the furrows (troughs) of the corrugations. 

Corrugations are important, because it increases the contact area, promotes mixing, creates turbulence, and it is the best way to improve plate heat exchangers.

But if you do not want  corrugations, you must use a more conductive material, and/or you use a working fluid that changes phases and take advantage of the latent heat.

At first, thanks for your answer. Secondly, I understood from your answer that there is no other geometrical techniques to achieve "increasing the contact area, promoting mixing, creating turbulence". 

I'm very graceful to your attachment,but

How about pins of short cylinder in Cross flow manner inside the rectangular flow channel of plate heat exchanger (PHX)?

Can this keep the fixed cost of PHX lower than corrugations?

Would this reduce the effectiveness?

Thanks for your sincere help.

If tappered pin Fin can provide lower Fin temperature (higher heat transfer coefficient) than corrugated ones. What about using this geometry enhancement in PHX instead of corrugations?

Can this reduce the cost of manufacturing the PHX?

Mr. Alatyar, the plate-frame exchanger as it obtains today is the culmination of its development for over a century. The use of pin fins as spacers has been tried before. But it is not a match to corrugated surfaces. In addition to thermal inferiority of pin fin spacers (heat transfer per unit of pumping power, for example), it is also mechanically inferior. The attaching of fins to the base surface will be more expensive, and difficult, to manufacture. The fins are short, hence their fin effectiveness (not the same as heat exchanger effectiveness) will be close to unity. Still they are secondary surfaces, while the corrugated surface is entirely primary surface. Finally, the corrugations increase the moment of inertia of the plate so that even sheets as thin as 0.5 mm can withstand impressive pressure differences. The number of support points (contact points) between a pair of plates cannot be matched by pin fins. If you try for the same number of contact points, the pressure drop will be enormous because of the bluff shape of the spacer fins.

To corrugate the plates requires heavy presses but the pressing of each plate takes just seconds and no heat! Imagine the pin fin joining process.

Contrary to earlier assumptions, there are few regions of flow stagnation in the plate space. Look for figures in the literature that show that the zig-zag flow occurs predominantly along the furrows (troughs) of the corrugations. 

Prof. Raghavan, your answer is clear and sufficient to my questions. Really Thanks 

I would formulate in a different manner: any way to reduce the boundary layer length and allow a better contact, turbulent, between fluid and wall is a solution. Corrugations have as goal even this boudary layer reduction. They reduce the heat transfer by conduction and increase the convection part.