This thesis project was developed within a collaboration between the Politec-nico di Milano and the heat exchanger manufacturer DeCa S.r.l. The aim ofthe project is upgrading MatriHX, which is a matrix based simulation code,developed in MatLab, for heat exchanger simulation. The project, started in2015, was developed by a series of theses from Politecnico di Milano .The new feature being developed is related to a geometrical descriptionupgrade. The new MatriHX engine can simulate performances of heat ex-changers with generic circuitries. The previous MatriHX could only solvecircuitries with equal coils.The heat exchanger circuitries are described with a matrix called RTMatrix. The RT Matrix has on the x-axis the dimension of the number oftubes in the heat exchanger and on the y-axis the dimension of the number ofrows in the heat exchanger. The RT Matrix stores fundamental informationfor the geometrical description of the heat exchanger such as inlet and outletposition and positions of the coil’s curves. The descriptive capability of theRT Matrix match the variety of existing machinery. Any type of circuitarrangements or inlet and outlet configuration can be described.Upgrading the geometrical description capability of MatriHX unveils theproblem of the unbalanced heat exchanger. Coils of different length havedifferent flow rates in them, to ensure the same pressure drop across themachine. This possibility was not taken into consideration in the previousengine. The heat exchanger unbalance is implemented with the other newfeatures.The final results of MatriHX are compared and validated against AspenEDR, reference commercial software in the market for heat exchange sim-ulations. The results show good agreement compared with Aspen with adistance that is within the 10% range. The computational time was not aparameter of interest for the implementation of MatriHX, however the newengine produces good results with a fast and robust convergence. The finalversion of MatriHX will be handed in DeCa S.r.l. that, in collaboration withPolitecnico di Milano, will continue the upgrading and testing of MatriHX.
Questo lavoro di tesi si inserisce in un progetto di ricerca pi ́u ampio svilup-pato in collaborazione fra il Politecnico di Milano e l’azienda produttrice discambiatori di calore Officine Meccanice DeCa S.r.l. L’obiettivo di questoprogetto ́e il potenziamento di MatriHX, software di simulazione matriciale,sviluppato in MatLab, per la simulazione di scambiatori di calore. Il progetto ́e iniziato nel 2015 ed ́e stato portato avanti attraverso una serie di tesi delPolitecnico di Milano [1], [2], [3], [4].La nuova funzionalit ́a sviluppata ́e relativa al miglioramento della de-scrizione geometrica. Il nuovo motore di MatriHX pu ́o simulare le prestazionidi scambiatori di calore con circuitazione generica. Il precedente motorepoteva risolvere solamanete circuitazioni con tubi tutti uguali.Le circuitazioni degli scambiatori di calore sono descritti attraverso unamatrice chiamata Matrice RT. La Matrice RT ha sull’asse x la dimensionedle numenro di tubi nello scambiatore di calore e sull’asse y la dimensonedel numero di ranghi. La Matrice RT contiene informazioni fondamentaliper la descrizione geometrica di uno scambiatore di calore come posizionedegli ingressi e delle uscite e la posizione delle curve dei circuiti. Le capacit ́adescrittive della Matrice RT vanno di pari passo con la variet ́a di macchinariesistenti. Qualsiasi tipo di circuitazione o configurazione di ingressi e uscitepu ́o essere modellata.Il miglioramento delle capacit ́a di descrizione geometrica di MatriHX riv-elano il problema dello sbilanciamento dello scambiatore. Tubi di differentelunghezza hanno differente portata fluente al loro interno, per garantire lastessa caduat di pressione sul macchinario. Tale possibilit ́a non era consider-ata nel precedenete motore di risoluzione. Il caso di scambiatore sbilanciato ́e implementato insieme alle altre nuove funzionalit ́a.I risultati finali di MatriHX sono confrontati e validati con Aspen EDR,software di riferimento commerciale per simulazioni di scambiatori di calore. Irisultati mostrano una buona compatibilit ́a con i risultati di Asepne EDR conuna distanza che si aggira intorno al 10%. Il tempo computazionale non eraun parametro di interesse per la implementazione di MatriHX. In ogni caso ilnuovo motore produce buoni risultati con una veloce e robusta convergenza.XV RiassuntoLa versione finale di MatriHX sar ́a consegnata in DeCa S.r.l. che, sempre incollaborazione con il Politecnico di Milano, continuer ́a lo sviluppo e il testingdi MatriHX.
Numerical upgrading of the MatriHX : implementation of a robust and complete algorithm for the simulation of heat exchangers with generic circuitries
VINCENTI, FERDINANDO
2018/2019
Abstract
This thesis project was developed within a collaboration between the Politec-nico di Milano and the heat exchanger manufacturer DeCa S.r.l. The aim ofthe project is upgrading MatriHX, which is a matrix based simulation code,developed in MatLab, for heat exchanger simulation. The project, started in2015, was developed by a series of theses from Politecnico di Milano .The new feature being developed is related to a geometrical descriptionupgrade. The new MatriHX engine can simulate performances of heat ex-changers with generic circuitries. The previous MatriHX could only solvecircuitries with equal coils.The heat exchanger circuitries are described with a matrix called RTMatrix. The RT Matrix has on the x-axis the dimension of the number oftubes in the heat exchanger and on the y-axis the dimension of the number ofrows in the heat exchanger. The RT Matrix stores fundamental informationfor the geometrical description of the heat exchanger such as inlet and outletposition and positions of the coil’s curves. The descriptive capability of theRT Matrix match the variety of existing machinery. Any type of circuitarrangements or inlet and outlet configuration can be described.Upgrading the geometrical description capability of MatriHX unveils theproblem of the unbalanced heat exchanger. Coils of different length havedifferent flow rates in them, to ensure the same pressure drop across themachine. This possibility was not taken into consideration in the previousengine. The heat exchanger unbalance is implemented with the other newfeatures.The final results of MatriHX are compared and validated against AspenEDR, reference commercial software in the market for heat exchange sim-ulations. The results show good agreement compared with Aspen with adistance that is within the 10% range. The computational time was not aparameter of interest for the implementation of MatriHX, however the newengine produces good results with a fast and robust convergence. The finalversion of MatriHX will be handed in DeCa S.r.l. that, in collaboration withPolitecnico di Milano, will continue the upgrading and testing of MatriHX.| File | Dimensione | Formato | |
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Descrizione: Numerical upgrading of the MatriHX: implementation of a robust and complete algorithm for the simulation of heat exchangers with generic circuitries
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https://hdl.handle.net/10589/165273