## THERMAL SCIENCE

International Scientific Journal

### THREE DIMENSIONAL CFD ANALYSIS OF BUOYANCY-DRIVEN NATURAL VENTILATION AND ENTROPY GENERATION IN A PRISMATIC GREENHOUSE

**ABSTRACT**

A computational analysis of the natural ventilation process and entropy generation in three-dimensional (3-D) prismatic greenhouse was performed using computational fluid dynamics (CFD). The aim of the study is to investigate how buoyancy forces influence airflow and temperature patterns inside the greenhouse having lower level opening in its right heated facade and also upper level opening near the roof top in the opposite cooled facade. The bottom and all other walls are assumed to be perfect thermal insulators. Rayleigh number is the main parameter which changes from 103 to 106 and Prandtl number is fixed at Pr =0.71. Results are reported in terms of particles trajectories, iso-surfaces of temperature, mean Nusselt number, and entropy generation. It has been found that the flow structure is sensitive to the value of Rayleigh number and that heat transfer increases with increasing this parameter. Also, it have been noticed that, using asymmetric opening positions improve the natural ventilation and facilitate the occurrence of buoyancy induced upward cross-airflow (low-level supply and upper-level extraction) inside the greenhouse.

**KEYWORDS**

PAPER SUBMITTED: 2015-10-15

PAPER REVISED: 2016-02-22

PAPER ACCEPTED: 2016-03-02

PUBLISHED ONLINE: 2016-03-12

**THERMAL SCIENCE** YEAR

**2018**, VOLUME

**22**, ISSUE

**Issue 1**, PAGES [73 - 85]

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