Impacts of thermally stratified medium on transient convective heat transfer between co‐axial horizontal fixed pipes: Applications of the thermal stratification

• Published in: Zeitschrift für angewandte Mathematik und Mechanik 2024-09, Vol.104 (9), p.n/a
• Main Authors: Nabwey, Hossam A., Bibi, Bakhtawar, Ashraf, Muhammad, Rashad, Ahmed M., Hawsah, Miad Abu
• Format: Article
• Language: English
• Subjects: Amplitudes; Boundary conditions; Convective heat transfer; Coupled walls; Dimensional analysis; Energy distribution; Equilibrium flow; Finite difference method; Flow distribution; Fluid flow; Heat; Heat transmission; Minimum flow; Nonlinear differential equations; Parameters; Partial differential equations; Pipes; Temperature dependence; Temperature distribution; Thermal stratification; Thermal stress; Time dependence; Unsteady flow
• ISSN: 0044-2267; 1521-4001
• DOI: 10.1002/zamm.202400052

Thermal stratification improves coaxial pipe systems’ efficiency and stability. Thermal stratification enables accurate temperature maintenance, reduces thermal stress, optimizes heat transmission performance, and minimizes usage of energy to guarantee the system's long‐term performance. The main aim of the current study is to investigate the impacts of thermal stratification on buoyancy force flow and thermal transmission between coaxial fixed pipes. In the present research, the applications of thermally stratified medium on transient convective heat transfer between two coaxial fixed pipes are studied. A two‐dimensional mathematical formulation in terms of mutually nonlinear partial differential equations is used to analyze the unsteady flow and temperature field between the co‐axial pipes, when the internal pipe is uniformly heated and the outer wall of the external pipe is placed at infinity from the surface of the inner fixed pipe. Flow is assumed along the axial direction of the internal pipe and stationary boundary condition is assumed at the surface of the inner pipe. The coupled equations of the simulated model are solved numerically by applying the Implicit Finite Difference Technique. The computed outcomes in the form of geometrical interpretation are highlighted by using the technically advanced software TECHPLOT‐360. Comprehensive detail of the obtained results for the non‐dimensional parameters included in the flow formulation is predicted for steady state velocity, temperature distribution, time‐dependent surface shearness and time‐dependent energy shearness in results and discussion section of the manuscript. The emphasis is placed on the thermal stratification parameter in the above mentioned chief quantities. From the obtained results, it is predicted that the fluid flow pattern and thermal distribution are both reduced for rising values of the thermal stratification parameter S = 0.001, 0.03, 0.05, and 0.07. Minimum flow and thermal profile are observed at S = 0.07. Further, the amplitude of the time‐dependent surface shearness is uniformly distributed throughout the medium and the amplitude of the time‐dependent energy shearness is reduced effectively for S = 1.0, 5.0, and 10.0.