دراسة تأثير هندسة الزعانف المعدلة على أداء وحدة التخزين الحراري ثلاثية القنوات المربعة

Studying the effects of modified fin geometries on the performance of triple _square channel thermal storage unit

Abstract

In energy storages system, it considered that the latent heat thermal energy to be highly significant than the sensible energy owing to its large storage energy densities in a unit mass at almost fixed thermal energy. The recent work uses internal and external fins to discuss a technique for enhancing heat transfer during the melting of phase change materials (PCM) in a triple-square channel heat exchanger (TSCHE). A 3-D numerical model is evolved employing FLUENT 2021 software. Pure conduction and natural convection are considered in the simulation. In the first case of the work, it was studied numerically by using RT42 paraffin wax, with copper triple- square channel. Finding the fins number, length of fin, mass flow rates, and phase change material (PCM) geometry in TSCHE is to study the influence of time for a comprehensive PCM melting. The study focused on the cases of fins, specifically Case A (without fins), Case B (with 4 fins), Case C (6 fins), and Case D (8 fins), all of which had a length of 42 mm. Also, case E (4 fins), case F (6 fins), and case G (8 fins) have a length of 47.6 mm and, the computational outcomes manifested that the case G (geometry of the PCM 8-cell) performed a shorter time to complete the melting of PCM, with a total melting time reduced to 29.2%. At the second case, the study was conducted numerically and experimentally: Paraffin wax RT64 is used, the system was made of stainless steel 304, the effect of volumetric flow rate, without and with using a fin. To validate the suggested model, experiments were carried out. The results of the simulation match those of the experimental part. The use of fins improved heat transfer during the paraffin wax melting process and thus reduced the melting time when using the same volumetric flow of (4, 8, and 16) l/min, respectively, the total enhancement of 29.68 %, 36.97%, and 48.7%.After that, the maximum difference was determined to identify the differences between the experimental and numerical results for the flow rates of HTF (4,8, and16) l/ min which were (4, 8, and 9) %, so the maximum difference was 9% for flow rate 16 l/ min.