Dimenzioniranje dimnjaka i simulacija povrata dimnih plinova u prostoriju

Zlatar, Dario (2009) Dimenzioniranje dimnjaka i simulacija povrata dimnih plinova u prostoriju. = Master's thesis (Bologna) , Sveučilište u Zagrebu, Fakultet strojarstva i brodogradnje, UNSPECIFIED. Mentor: Virag, Zdravko.

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Abstract (Croatian)

U radu je izvršeno dimenzioniranje dimnjaka na koji je priključeno jedno plinskog trošilo snage 24 kW. Korišten je postupak proračuna dimnjaka prema europskoj normi EN 13384, te je načinjen računalni program u programskom jeziku Python. Rezultati proračuna su uspoređeni s rezultatima komercijalnog programa KESA ALADIN za proračun dimnjaka, koji se temelji na istoj normi, a ima ugrađeno automatsko pridruživanje podataka (standardnih promjera, izbora koeficijenata i sl.), te baze podataka koje specificiraju proizvođači opreme. Slaganje rezultata vlastitog proračuna s rezultatima komercijalnog programa je vrlo dobro. U drugom dijelu rada su analizirane prijelazne pojave strujanja dimnih plinova prilikom uključivanja plinskog trošila u ljetnim mjesecima. Poznato je da se za vrijeme vrućih ljetnih dana događaju trovanja ugljičnim monoksidom, koja su uzrokovana neispravnošću plinskog trošila (nepotpunim izgaranjem) i povratom dimnih plinova u prostoriju. Ako dimnjak prolazi zidovima klimatiziranih prostorija, zrak u dimnjaku je hladniji od okolnog te se u dimnjaku ustaljuje natražno strujanje zraka, iz okoline u prostoriju. Nakon uključivanja plinskog trošila dimni plinovi prvo trebaju zaustaviti to natražno strujanje zraka, te okrenuti smjer strujanja u dimnjaku. Za to vrijeme dimni plinovi će ulaziti u prostoriju umjesto u dimnjak. Analizom utjecajnih parametara je zaključeno da će na vrijeme potrebno da se prekine strujanje dimnih plinova u prostoriju utjecati duljina horizontalnog dijela vezne cijevi (spoj trošila na dimnjak). Simulirano je uključivanje plinskog trošila za tri različite duljine vezne cijevi: 0,7, 1,5 i 2,5 m, te je dobiveno da vrijeme uspostave normalnog rada dimnjaka kod cijevi duljine 0,7 m iznosi oko 15 s, kod cijevi duljine 1,5 m oko 135 s, dok kod cijevi duljine 2,5 m, u 95-toj sekundi trend pokazuje da vjerojatno neće niti doći do uspostave normalnog rada dimnjaka.

Abstract

In this work the sizing of the chimney that is connected to a gas appliance power 24 kW has been preformed. The used calculation method was in according to the European standard EN 13384. An own computer program was developed in the programming language Phyton. The calculation results of the developed program were compared with the results of commercial program KESA ALADIN which is based on the same standards, and has a builtin automatic data assignation (standard pipe diameters, selection of needed coefficients, etc.) and data bases which are specified by the equipment manufacturers. The agreement of the obtained results with the results of commercial programs is very good. In the second part of the transients of the gas flow caused by the gas appliance turn on while the chimney is cold (the summer time). It is known that during hot summer days the accidents due to carbon monoxide poisoning occurs. These are consequences of improperly maintenance of the gas appliances (because of the incomplete combustion) and the returning of the gas fumes back into the room. If the chimney passes through the walls of airconditioned rooms, the air in the chimney is cooler than the surrounding one, and the chimney air flow is backwards from outside into the room. After turning on the gas appliance, the gas fumes should first stop the chimney backward airflow and after that turn the flow direction from the room to outside. During that time the gas fumes will enter the room instead of the chimney. From the analysis of influence parameters it has been concluded that the time needed to establish right flow direction depends on the length of the horizontal part of the tie tube (the connection of the appliance into the chimney). Transient gas flows were simulated for three lengths of tie tube. For the tube length of 0,7 m, the normal chimney flow was achieved in 15 s, for the tube length of 1,5 m in 135 s, and obtained trends in the simulation with tube length of 2,5 m shows that the normal chimney flow will probably not be achieved.

Item Type: Thesis (Master's thesis (Bologna))
Uncontrolled Keywords: dimenzioniranje dimnjaka; prijelazne pojave strujanja dimnih plinova; natražno strujanje
Divisions: 500 Department of Energy, Power Engineering and Environment > 520 Chair of Fluid Mechanics
Date Deposited: 22 Sep 2014 18:00
Last Modified: 24 Oct 2019 12:17
URI: http://repozitorij.fsb.hr/id/eprint/719

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