Ventilation duct sizing tools - tradition and modernity
Journal Title: Вісник Національного університету "Львівська політехніка". Серія "Теорія та практика будівництва" - Year 2016, Vol 0, Issue 844
Abstract
One of the most important problems in the hydraulic design of various building services systems is the calculation of the friction factor involved in Darcy-Weisbach equation. Ventilation duct sizing is a good case study, showing how classic, old-school design tools collide with modern instruments of the digital era. The friction factor is a function of Reynolds number, relative roughness and flow regime. Apart from the graphical representation in Moody’s chart, those variables are packed in the famous Colebrook-White equation, widely accepted by engineers and scientists. Unfortunately, this equation is an implicit one and must be solved using numerical methods. This is a major disadvantage for the average engineer, who often wants a quick result, if possible using a simple, explicit equation. Therefore, the traditional hydraulic design tool offered to engineers in handbooks was a chart (nomograph), giving directly the pressure drop per unit length (Pa/m), thus hiding the complexity of finding the friction factor. Later, when personal computers became available, the tactics have changed: Colebrook-White equation needed to be replaced by a simpler one. So, during the last two decades, many authors proposed their own explicit equations, more or less complicated, making the choice of young engineers even more difficult than before. The present paper tries to make an overview of the most used alternatives to Colebrook-White equation, analyzing their complexity and mathematical accuracy for different Reynolds numbers and relative roughnesses. Also, some modern software instruments for ventilation duct sizing were investigated.
Authors and Affiliations
C. Bacotiu, F. Domnita, A. Hotupan, P. Kapalo
Keywords
Related Articles
- EP ID EP230908
- DOI -
- Views 77
- Downloads 0
ДЕФОРМАТИВНІСТЬ ВУЗЛІВ ДЕРЕВ’ЯНИХ КОНСТРУКЦІЙ НА З’ЄДНАННЯХ ТИПУ “СТАЛЬ-ДЕРЕВИНА”
Nowadays design of timber buildings and constructions growth up. It is connected with the dissemination of eco-technologies, efficient energy-saving buildings, rapid constructing, inexpensive solutions and addicting to s...
Аналіз та оцінка ефективності використання теплової ізоляції в опалювальній котельні
The heating supply of residential areas in many cities of Ukraine is central. The heat sources of central heating are heating boiler houses with hot water boilers. Heating boiler houses, usually located far from resident...
Оптимальне розташування вирівнювальної пластини в конструкції дифузора для підвищення тискових та витратних характеристик вентиляційних систем
At work investigates the incoming flow and its alignment to the ventilation system elements, located directly outside a radial fan. The efficiency of the ventilation system depends on the improvement of its aerodynamic c...
Особливості вертикальної гідроізоляції стін із кремнійорганічних рідин та сумішей на їх основі
This article presents the results of a study liquids production ZDP “Kremniypolimer” for their application for obtaining or renewal of vertical waterproofing by surface impregnation and waterproofing during repair work t...
ANALYSIS OF THERMAL PROPERTIES OF FLOORS IN HEATED BUILDINGS
The article discusses some thermal properties of floors and floorings, such as heat transfer and heat absorption. It was pointed out that there are no specific requirements in the field of heat absorption by floor constr...