Heat Exchangers: Design Considerations. Parallel Flow. Counterflow. Heat Exchanger Types. Types. Heat exchangers are ubiquitous to energy conversion and utilization. They involve heat exchange between two fluids separated by a solid and encompass a wide range of flow configurations.
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Heat Exchangers:Design Considerations
Heat Exchanger Types
Heat exchangers are ubiquitous to energy conversion and utilization. They involve heat exchange between two fluids separated by a solid and encompass a wide range of flow configurations.
Unfinned-One Fluid Mixed
the Other Unmixed
direction (y) is prevented for the finned tubes, but occurs for the unfinned condition.
One Shell Pass and One Tube Pass
shell-side fluid, both of which enhance convection.
One Shell Pass,
Two Tube Passes
Two Shell Passes,
Four Tube Passes
one or both fluids is a gas.
flow passages, and laminar flow.
(a) Fin-tube (flat tubes, continuous plate fins)
(b) Fin-tube (circular tubes, continuous plate fins)
(c) Fin-tube (circular tubes, circular fins)
(d) Plate-fin (single pass)
(e) Plate-fin (multipass)
Tubular Exchanger Manufacturers Association
Overall Heat Transfer Coefficient
1 / U A = 1 / h1 A1 + dxw / k A + 1 / h2 A2
U = the overall heat transfer coefficient (W/m2K)
A = the contact area for each fluid side (m2)
k = the thermal conductivity of the material (W/mK)
h = the individual convection heat transfer coefficient for each fluid (W/m2K)
dxw = the wall thickness (m)
n = 0.4 for heating (wall hotter than the bulk fluid) and 0.33 for cooling (wall cooler than the bulk fluid)
Evaluation of depends on the heat exchanger type.
A Methodology for Heat Exchanger
- The Log Mean Temperature Difference (LMTD) Method -
Overall Energy Balance
Special Operating Conditions