1801 KB30 KB199920252016Bobič, MihaDiaci, JanezGolobič, IztokPribošek, Jakaletnik:62številka:nr. 1str. 3-10ISSN:0039-2480COBISSID_HOST:14444827URN:URN:NBN:SI:doc-SFD8HCA4enZveza strojnih inženirjev in tehnikov Slovenije etc.Strojniški vestnikeksperimentalna validacija numeričnih analizmetoda sledenja delcevoptimizacija ploščnih prenosnikovperiodična optična distorzijavaloviti ploščni prenosniki toploteCorrecting the periodic optical distortion for particle-tracking velocimetry in corrugated-plate heat exchangers|o improve current methods for the experimental validation of numerical simulations in corrugated-plate heat exchangers (CPHEs), a full-field quantitative velocimetry of fluid flow is required. This paper investigates the application of particle-tracking velocimetry (PTV) to modified CPHEs. For this, an experimental CPHE unit with a transparent, corrugated upper plate was built. We show that by viewing through a corrugated, refractive interface, a complex periodic optical distortion is introduced, that affects and corrupts the estimated particle trajectories. As this problem cannot be addressed using existing calibration techniques, we propose a novel calibration algorithm for periodic optical distortion. The algorithm relies on the automatic detection of nonlinear distortion using a checkerboard target place within the CPHE unit. The calibration is first made on a coarse grid and subsequently refined by a set of low-order periodic basis functions in order to seize the periodic nature of the deformation field. The proposed algorithms have been applied to a test case with known, uniform particle velocities in order to demonstrate the performance. When applied to a real case, a reduction in the systematic positional error by 35 % was demonstratedOptimizacija valovitih ploščnih prenosnikov toplote je bila dotlej omejena na numerične CFD simulacije, pri čemer pa spričo zaprte konstrukcije tovrstnih prenosnikov, eksperimentalna validacija teh simulacij ostaja nenaslovljena. Ker so tokovni pojavi v valovitih prenosnikih navadno kompleksne narave, je za uspešno validacijo nujna kvantitativno spremljanje celotnega tokovnega polja znotraj prenosnikov. V ta namen smo na valovitih ploščnih prenosnikih toplote vpeljali metodo sledenja delcev. Za neposredno vizualizacijo toka v prenosniku je bil izdelan lasten eksperimentalni sistem, kjer je bila ena od kovinskih plošč ploščnega prenosnika zamenjana s prozorno polimerno ploščoTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo