Three-dimensional numerical simulation of heat transfer characteristics in cooling systems using phase change materials in the rectangular containers

Other Title(s)

التمثيل العددي الثلاثي البعد لخصائص انتقال الحرارة في أنظمة التبريد التي تستعمل مواد متغيرة الطور في الحاويات المستطيلة

Dissertant

al-Khazali, Ali Sadun Falih

Thesis advisor

Muhammad, Ahmad K.

Comitee Members

Salman, Yasin Khudayr
Ismail, Munir Abd al-Jalil
Abbud, Falah Asi

University

University of Basrah

Faculty

Engineering College

Department

Department of Mechanical Engineering

University Country

Iraq

Degree

Master

Degree Date

2012

English Abstract

In this study the performance of latent cool thermal energy storage system is investigated numerically to use as the cold storage.

The Navier-Stokes equations (momentum equations) of the heat transfer fluid (HTF) flow are solved in laminar, 3-D, steady state, incompressible, and no slip Conditions ; while the energy equation of heat transfer fluid is solved for unsteady state condition.

The heat conduction in the phase change material (paraffinic hydrocarbon) (PCM) and the solid partitions are considered as unsteady 3-D heat conduction problem using the effective heat capacity method for PCM.

The governing equations are discretized using finite-volume method (explicit method)-upwind differencing scheme, and then these are solved using SIMPLE algorithm method on staggered grid with FORTRAN code.

The pressure correction method is used to obtain the velocity distribution, and then the energy equations for the fluid and the periphery domain (solid and PCM) are solved simultaneously as second step.

The study included two main steps.

First, velocity of HTF, temperatures and solid fraction distribution are studied, yielding detailed information on the HTF velocity behavior under effect of different values of the Re, also give information about phase and temperatures distribution inside the PCM and the HTF during the transient phase-change process.

Then, a detailed parametric investigation is performed, including effects of Reynolds number, Stefan number, and horizontal partition thickness, dimensionless initial temperature of the PCM, aspect ratio and container height on the performance of the latent cool thermal energy storage system.

These parameters effect on the dimensionless average channel surface temperature, Nusselt number, dimensionless HTF outlet bulk temperature, dimensionless PCM temperature, solid fraction, solid front in -3D and the cumulative cool energy storage in different levels.

Also, it was found from the obtained results that the dimensionless initial temperature of the phase change material (θpi) and horizontal partition thickness (Hs) not have very important effect on thermal performance of the cool thermal energy storage (CTES) system, while the Reynolds number (Re), Stefan number(Ste), aspect ratio (αc) and container height (Hp) play an important role during solidification process and has a strong effect on performance of the cool thermal energy storage (CTES) system.

Also, it was found that the effect of Stefan number (Ste) on Nusselt number of HTF is not significant.

The present effective heat capacity model is compared with the available enthalpy model of other authors, and the comparison showed relatively good agreement.

Main Subjects

Mechanical Engineering

Topics

• Air conditioning

No. of Pages

139

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-317655