A shellandtube heat exchanger is made of tubes with 1 outsid

A shell-and-tube heat exchanger is made of tubes with 1\" outside diameter, stainless steel and 18BWG. The tubes are arranged in a 60 degree triangular pitch of 1.25\". If the shell-side fluid is water at 250 degree F flowing at a velocity of 1 ft/s. check by calculation if a baffle spacing of 25\" will cause collision damage

Solution

Soltution

Using Characteristics strouhal number to find out the value of frequancy of veortex sepration from the tube surface

             S = Df / u

           for an in line tube bank    s = 0.2 + exp ( -1.2 ( bi / D)^1/4 )

                 S = 0.2 exp (( - 1.2 ( 1.25 / 1)^1/4 )

                 S = 0.366

            Subsituting the value in above equation we will get

                    f = su / D =( o.366 * 2 ) / I

                     f = 0.732

The natural frequancy of vibration is given by the following relationship

                f = B / 2pi I² ( EI / m ) ^0.3

                    ^{SO , assuming the value of B as 10 according to given conditions , we got the result.}

                                      ^{For safe conditions , f should be at least should be lesser than by fi by 20%.}