Thesis Defense - Enes Abdülhakim Öksüz (MSME)

Enes Abdülhakim Öksüz - M.Sc. Mechanical Engineering

Prof. Mehmet Arık – Advisor

Asst. Prof. Altuğ Başol – Co-advisor

Date: 17.08.2021

Time: 11:00

Location: This meeting will be held ONLINE. Please send an e-mail to gizem.bakir@ozyegin.edu.tr in order to participate in this defense.

AN EXPERIMENTAL RESEARCH ON THE EFFECTS OF FROST FORMATION ON DIFFERENT ENVIRONMENTAL CONDITIONS AND SURFACE CONFIGURATIONS

Thesis Committee:

Prof. Mehmet Arık, Özyeğin University

Asst. Prof. Altug Başol, Özyeğin University

Asst. Prof. Polat Şendur, Özyeğin University

Prof. Kadri Süleyman Yiğit, Kocaeli University

Asst. Prof. Murat Çelik, Boğaziçi University

Abstract:

Frost formation on finned surfaces is observed on heat exchangers in cooling systems such as refrigerators and air conditioners. Accumulated frost on finned surfaces blocks the air flow in between fins and reduces the effective surface area and it creates an additional resistance for heat transfer. The frost accumulation on finned surfaces increases the energy consumption of a cooling system and needs to be mitigated by the design of the finned surfaces. In this experimental study, the effects of air velocity, relative air humidity, surface temperature, fin length, fin space, surface orientation, and surface coating on the heat transfer performance of the finned surface have been investigated. The heat transfer rate through the finned surface was measured during the experiment using an in-house built Heat Flux Measurement System (HFMS). Experiments showed that frost accumulation on finned surfaces blocks the air penetration into fin gaps and results in a sharp drop in the heat transfer rate. It has been found that high relative humidity, high incoming air velocity, high fin length increases the heat transfer rate from the finned surface by reducing the negative impact of frosting on the heat transfer rate. Condensed water droplets occur on the surfaces since higher parameter values provide higher heat transfer rates. Condensed water droplets turn to ice with the beginning of the frost formation. The high thermal conductivity of ice increases the effective thermal conductivity of frost and provides higher heat transfer rates. Narrow fin space is found to be disadvantageous under frosting conditions. The small gap between fins is easily blocked by the frost and the effective surface area of the finned surface is heavily reduced.

Bio: 

Enes Abdülhakim Öksüz was born in İstanbul in 1992. He received his B.Sc. degree in Mechanical Engineering from the Karadeniz Technical University, Trabzon in 2017. He studies M.Sc. degree in Mechanical Engineering at Özyeğin University. He is a member of EVATEG, one of the university's largest research groups. He investigates the effects of frost formation on heat transfer for different conditions with Prof Mehmet Arık.