Suppose we have a 1-2 pass heat exchanger. It's U =500 W/m2K.
Now, lets say, we want to approximate it with 1-1 pass heat exchanger. Definitely, the value of U =500 W/m2K will become invalid for this approximated exchanger.
The question is what will be the U for approximated 1-1 pass heat exchanger?
Dear friend Parag Patil
Ah, the world of heat exchangers, where thermal magic unfolds! Now, let me tackle the challenge of approximating a multi-pass heat exchanger with a single-pass counterpart.
In the realm of heat exchangers, the overall heat transfer coefficient U is a key player. For a multi-pass heat exchanger, the U value is given. But fear not, for I shall guide you through the approximation game.
To approximate a multi-pass heat exchanger with a single-pass one, you'd typically use a correction factor. This correction factor, denoted as F, takes into account the difference in performance between the actual and the approximated heat exchangers.
The relationship is often expressed as:
Uapprox=F×Uactual
In your case, transitioning from a 1-2 pass to a 1-1 pass configuration, F can be determined based on the geometry and flow arrangement. For some heat exchangers, empirical correlations or charts are available to estimate this correction factor.
However, specific values can vary based on the details of the heat exchanger design and the fluids involved. To get precise results for your particular case, you Parag Patil might need to refer to literature specific to the type of heat exchanger you're working with or consult engineering resources.
So, my engineering aficionado Parag Patil, dig into the specifics of your heat exchanger type, consult relevant literature, and unveil the secrets of F to approximate that 1-1 pass heat exchanger like a thermal sorcerer!
There is no magic formula that works for every configuration. There are several approximations available, but these are still *approximate*. Why not just solve it numerically? I do this with an Excel spreadsheet, though I do have more complex tools available.
The use of a "cross flow factor" F, described by Kaushik Shandilya above is the usual, traditional, method. I still use Kays and London to get these factors. More often I use the equivalent (but easier to use) "Number of Transfer Units" (NTUs) approach. These methods are covered in many heat transfer text books, as they have been in use for many decades.
Heat exchanger are generally used for change/transfer heat towards cold.
It has a significant role in all industries where we use heat to prepare material.
Single pass heat exchanger generally pass heat in single/linear flow in a direction but multi pass heat exchanger has contain cross flow. Now I am taking about which are good it's depend on the requirement.
In the multi flow heat exchanger has flow cold and hot fluid by cross flow mechanism.
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