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Heat Exchangers

2 tools in the Fluids and Heat Transfer area.

Heat Exchanger Effectiveness

Effectiveness–NTU analysis of a two-stream heat exchanger. In rating mode the overall conductance UA is known and the tool finds the heat transferred and both outlet temperatures; in sizing mode one outlet temperature is the target and the tool finds the NTU and UA that reach it. Six flow arrangements are covered (counterflow, parallel flow, crossflow with both streams unmixed, crossflow with one stream mixed, and shell-and-tube with one or more shell passes) with the closed-form ε–NTU relations; the log-mean temperature difference and its correction factor are reported as a check, and the ε–NTU chart of the arrangement is drawn with the case on it.

Heat Exchanger Sizing and Pressure Drop

Thermal design of a two-stream heat exchanger by the LMTD method: the duty and the missing outlet temperatures from the energy balance, the log-mean temperature difference with the correction factor F of the arrangement (Bowman–Mueller–Nagle closed forms for 1-2 and 2-4 shell-and-tube, exact series for crossflow), the film coefficients on both sides (Dittus–Boelter, Gnielinski or Sieder–Tate in the tubes; Kern's method on the shell side), the overall coefficient clean and fouled, the area required against the area the geometry provides, and the pressure drop on each side against an allowable. Shell-and-tube exchangers are sized (shell diameter, tube count, baffles) or rated; double-pipe, gasketed-plate and air-cooled finned-tube options are included. Water and air properties come from the IAPWS-IF97 and NASA Glenn libraries; other fluids are entered.

1 worked example reproduced, listed on the tool page.

Other Fluids and Heat Transfer sections

Pipe Flow · Pumps and Fans · Compressible Flow · Conduction · Convection · Radiation · Thermodynamic Cycles · Fluid Properties