Pressure drop across heat exchangers

[isaivani]

I have 2 heat exchangers which are connected in series.The only info I have about them is their heat transfer area.How can I go a pressure drop calculation over them?The product comes from a reactor ,goes through the heat exchangers and is pumped back into the reactor.

 

[quark]

Refer to Process Heat Transfer by DQ Kern. You have all emperical formulae there, if they are S&T HXs.

 

[quark]

BTW, why can't you measure?