Do baffle plates installed in the shell side of a tubular heat exchanger also increase the flow velocity?
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Looking at today’s daily question: The purpose of installing baffle plates inside the shell side of a tubular heat exchanger is to __increase the flow velocity of the fluid in the shell side_, thereby increasing the convective heat transfer coefficient in that side. Isn’t it the case that the higher the flow is in a straight line, the faster it is? How can adding baffles increase the flow velocity?
At the same flow rate, the smaller the flow area, the higher the flow velocity. The baffle plates reduce the flow area, which leads to an increase in flow velocity and turbulence, thereby accelerating heat transfer
After reading your explanation, my understanding is as follows: For the same volume of flow, if the path length is greater, the flow velocity increases, which in turn improves the heat exchange efficiency. Baffles serve to increase the length of the fluid path
According to the formula for flow rate, flow rate = velocity * cross-sectional area, and the velocity is independent of the length of the path. It is only in a space with a fixed volume like a heat exchanger that an increased flow path length equates to a reduced flow area, which creates this illusion!
The answer is upstairs! The baffle plates in a tubular heat exchanger not only prevent fluid short-circuiting and increase the flow velocity of the fluid, but also force the fluid to flow across the tube bundle in a cross-flow manner multiple times along a specified path, thereby greatly increasing the level of turbulence.
I think this answer is not accurate enough. Adding baffles does not increase the overall flow velocity of the fluid on the shell side, but it can increase the local flow velocity of the fluid at the locations of the baffles. This leads to an increase in the local Reynolds number and thus to localized turbulence, which in turn improves the efficiency of convective heat transfer.
With all other conditions remaining unchanged, and the flow velocity in the inlet section or the outlet main pipe staying constant, the function of the baffle is to increase the pathways inside the equipment in order to achieve better heat exchange; the explanation given above makes more sense
Increase the shell-side fluid velocity, prolong the residence time, and raise the shell-side convective heat transfer coefficient.