Pressure loss in shell side of shell&tube heat exchanger with baffle plates

[virk]

Following scenario:
Shell&tube heat exchanger will be designed with f.e. pressurized water flowing on shell side. Baffles are to be installed to increase heat transfer. Now my topic: I would assume that there will be "normal" friction losses due to contact of water with wall; but also I assume there will be a considerable amount of pressure loss due to the flow regime: Water flows "horizontally" through the heat exchanger and then will be accelerated to flow through the considerable smaller passage above/beneath the baffle. After having passed the baffle water flow is deaccelerated again. This should happen at every baffle. If I for example calculate:

speed above baffle: 1,5m/s
speed horizontally: 0,5 m/s

a pressure loss due to impulse losses of about 900 Pa per baffle. This would result in 1,3 bar in a heat exchanger of 8 bundles with 18 baffles each. This rough calculation would be in a comparable range of what calculation programs give as result.

My question: 1) Are my considerations correct? 2) How do programs etc. handle this topic. I am a little bit lost here.

Eventually more to follow on request

 

[georgeverghese]

Shellside pressure drop and heat transfer coeff calcs are well detailed in the chapter on heat transfer equipment in Perry - this references the well known study made by Bell and Taborek.
Also see "Process Heat Transfer" by DQ Kern.