Search results for "Micro heat exchanger"
showing 5 items of 5 documents
Investigation of Flow and Heat Transfer in Corrugated-Undulated Plate Heat Exchangers
2000
An experimental and numerical investigation of heat transfer and fluid flow was conducted for corrugated-undulated plate heat exchanger configurations under transitional and weakly turbulent conditions. For a given geometry of the corrugated plates the geometrical characteristics of the undulated plates, the angle formed by the latter with the main flow direction, and the Reynolds number were made to vary. Distributions of the local heat transfer coefficient were obtained by using liquid-crystal thermography, and surface-averaged values were computed; friction coefficients were measured by wall pressure tappings. Overall heat transfer and pressure drop correlations were derived. Three-dimen…
Large-Eddy Simulation of Flow and Heat Transfer in Compact Heat Exchangers
1994
LES results are presented for different heat exchanger geometries. Subgrid terms were usually computed by the Smagorinsky model; preliminary comparative results are also given for the ‘dynamic’ subgrid model. The numerical methods used were those implemented in a commercial general-purpose code (CFDS-FLOW3D); they included a finite-volume approach, colocated body-fitted grids, central differencing for the advection terms, the SIMPLEC algorithm, and Crank-Nicolson time stepping. Predictions arc compared with experimental measurements (including local Nu distributions), and with results from a low-Reynolds number k-e model. In most cases, LES was more ‘robust’ and required little more CPU tim…
Flow and Heat Transfer in Corrugated Passages: Direct and Large Eddy Simulation and Comparison with Experimental Results
1993
Direct and large-eddy numerical simulations are presented for the transitional and turbulent flow with heat transfer in corrugated passages, representative of compact heat exchangers such as rotary air preheaters (regenerators), at Reynolds number ranging from 103 to 104. Pressure drop and heat transfer results are compared with wind-tunnel experimental data; the agreement is quite satisfactory, and superior to that obtained by more traditional methods.
Experimental and Numerical Simulations of Flow and Heat Transfer in Heat Exchanger Elements Using Liquid Crystal Thermography
2004
Experimental and numerical investigation of heat transfer and fluid flow were conducted for classic heat exchanger elements (flat plate with fin-tubes in-line, staggered and with vortex generators) and corrugated-undulated ducts under transitional and weakly turbulent conditions. The dependence of average heat transfer and pressure drop on Reynolds number and geometrical parameters was investigated. Distributions of local heat transfer coefficient were obtained by using liquid crystal thermography and surface-averaged values were computed. Three-dimensional numerical simulations were conducted by a finite-volume method using a low-Reynolds number k-e model under the assumption of fully deve…
Local Effects of Longitudinal Heat Conduction in Plate Heat Exchangers
2007
Abstract In a plate heat exchanger, heat transfer from the hot to the cold fluid is a multi-dimensional conjugate problem, in which longitudinal heat conduction (LHC) along the dividing walls often plays some role and can not be neglected. Large-scale , or end-to-end, LHC is always detrimental to the exchanger’s effectiveness. On the contrary, if significant non-uniformities exist in the distribution of either convective heat transfer coefficient, small-scale , or local, LHC may actually enhance the exchanger’s performance by improving the thermal coupling between high heat transfer spots located on the opposite sides of the dividing wall.