One-Dimensional Simulation and Experimental Investigation of the Shell-Integrated Condenser of the Underwater Closed-Loop Thermal Propulsion System

In order to understand heat transfer of the shell condenser in the closed-loop thermal propulsion system of the unmanned underwater Vehicles, the one-dimensional thermal model based on the hull-integrated condenser with helix channels is developed. After this, experimental research is conducted. Through the experiment data and theoretical calculation results compared, the accuracy of the heat transfer mathematical model is verified, and the correlation formulas about heat transfer are developed. In addition, the impacts of three factors on the performance of the shell condenser are investigated, including cross-sectional area of the cooling channel, flow rate and temperature of inlet steam. The research results indicate that the model and the correlation formulas about heat transfer is reliability and accuracy, which can provide a theoretical basis for simulation and optimization design of the shell condenser.

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Numerical Analysis for Heat and Mass Transfer of Granular Flow in a Duct by the Discrete Particle Simulation

Volume 5: Fuel Cycle and High and Low Level Waste Management and Decommissioning; Computational Fluid Dynamics (CFD), Neutronics Methods and Coupled Codes; Instrumentation and Control ◽

10.1115/icone17-75762 ◽

2009 ◽

Author(s):

Tomohiko Yamaguchi ◽

Kuniyasu Kanemaru ◽

Satoru Momoki ◽

Toru Shigechi ◽

Ryo Fujiwara

Keyword(s):

Heat Transfer ◽

Temperature Distribution ◽

Energy Equation ◽

Continuous Phase ◽

Particle Simulation ◽

Two Dimensional ◽

Discrete Particle ◽

One Dimensional ◽

Discrete Particle Simulation ◽

Dimensional Simulation

The solid-gas or liquid-gas two phase flow has many industrial applications such as spray drying, pollution control, transport systems, fluidized beds, energy conversion and propulsion, material processing, and so on. Though the solid-gas multiphase flow has been studied experimentally and numerically, the transport phenomena have not been cleared due to its complexity, computational time and economical costs for the hardware. In this study the heat and mass transfer of solid-gas collision dominated flow is analyzed by the Discrete Particle Simulation (DPS), a kind of the Dispersed Element Method (DEM)[1]. This method describes the discrete phase and the continuous phase by Lagrange and Euler methods respectively, and has been used to simulate the multiphase flow of various geometrical systems. In order to analyze the thermal field we took account of the energy equation and heat conduction between colliding particles. The heat transfer rate is summation of conductive heat transfer and convective heat transfer. Furthermore, the fluid flow has a two dimensional velocity profile, because the void fractions are analyzed as two dimensions. But momentum space has not been resolved by the two dimensional simulation. We call this method, the quasi two-dimensional simulation in this paper. To obtain the temperature distribution of the continuous phase the energy equation is solved in addition to the momentum equations. We treated the interaction between continuous and discrete phases as one and two way couplings. The positions, the momentum and the temperature information of particles and the velocity and the temperature distribution of the fluid were obtained as functions of time from results of these numerical simulations. When the hot air that is suspending small glass particles flows in a duct from bottom up, we traced the particles and got the temperature distribution of fluid and compared with the former results of one-dimensional flow. At the beginning, the cooler particles decrease the fluid temperature near the bottom of the vessel. The temperature profile of the particles obtained by the one-dimensional simulation is as same as quasi two-dimensional simulation. After 0.5 second the particles cool the downstream air. At 1.2 second, particles do not decrease the air temperature because the temperatures of particles are close to the inlet temperature of the air.

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Numerical Project for the Undergraduate Heat Transfer Course

Volume 5: Education and Globalization ◽

10.1115/imece2017-72538 ◽

2017 ◽

Author(s):

Dani Fadda

Keyword(s):

Heat Transfer ◽

Solid Body ◽

Three Dimensional ◽

Engineering Curriculum ◽

One Dimensional ◽

Conduction Heat Transfer ◽

Heat Transfer Simulation ◽

The Difference ◽

Dimensional Simulation ◽

Classroom Time

A numerical simulation project, described in this paper, was assigned in an undergraduate heat transfer course in the mechanical engineering curriculum. This project complemented the heat transfer lecture course and its corresponding heat transfer lab. It was used to help students visualize and better understand the difference between conduction heat transfer which occurs within a three-dimensional solid body and the convection and/or radiation which occur at the surface of the solid body. It also allowed the students to generate and compare results of one dimensional heat transfer calculations to three dimensional simulation results. The project contained well defined deliverables and an open-ended deliverable which allowed students to be creative. It gave the students reason to discuss the course outside the classroom. It allowed students to use SolidWorks heat transfer simulation and manage a MATLAB script without taking classroom time. It was appreciated and enjoyed by the students.

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Optimization Design of Turbine Blade Cooling Structure Based on Conjugate Heat Transfer

Volume 7C: Heat Transfer ◽

10.1115/gt2020-14416 ◽

2020 ◽

Author(s):

Mingrui Wang ◽

Huiren Zhu ◽

Yang Xu

Keyword(s):

Heat Transfer ◽

Optimization Design ◽

Conjugate Heat Transfer ◽

Turbine Blades ◽

Optimized Design ◽

Cooling Effectiveness ◽

Film Cooling Effectiveness ◽

Baseline Design ◽

Calculation Results ◽

Cylindrical Holes

Abstract Conjugate heat transfer (CHT) has been widely used in the analysis on flow field and heat transfer of turbine blades. In this paper, a baseline design of turbine rotor blade is selected. By improving the arrangement of film holes, turning cylindrical holes into laid back fan-shaped holes in the pressure surface (PS) and suction surface (SS), and reducing the radially inclined angle of film holes on the leading edge (LE), an optimized design (OPT) is created. Grid independence validation is conducted by comparing the pressure and temperature distributions adopting three different numbers of grids. In order to select a suitable turbulence model, experiment is performed and its values are compared with the calculation results of three different turbulence models. The distributions of static pressure, static temperature, overall cooling effectiveness and streamlines of cooling flow are compared between the OPT and baseline design by the numerical calculation results of CHT. Furthermore, the adiabatic film cooling effectiveness is calculated and the cooling performances between cylindrical holes and laid-back fan-shaped holes are compared. At last, the flow and heat transfer mechanisms are analyzed and the forming causes of low or high temperature regions on the blade are explained. Calculation results show that compared with the baseline design, the area average temperature drops by 2.6% on the PS and by 3.7% on the SS. The area average overall cooling effectiveness increases by 9.3% on the PS and by 14.1% on the SS. The cooling performances are promoted greatly on the PS and SS but change little on the LE and TE. Obviously, the improvements are successful.

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Heat Transfer Induced by Electron Tunneling Between Two Metal Plates

Volume 8: Heat Transfer and Thermal Engineering ◽

10.1115/imece2019-11365 ◽

2019 ◽

Author(s):

Bojing Yao ◽

Liang Pan

Keyword(s):

Heat Transfer ◽

Radiative Heat Transfer ◽

Quantum Tunneling ◽

Radiative Heat ◽

Electron Tunneling ◽

Electron Motion ◽

One Dimensional ◽

Metal Plates ◽

Calculation Results ◽

Vacuum Gap

Abstract We calculated the heat transfer caused by electron tunneling between two semi-infinite metal plates separated by a vacuum gap, which are made of the same material. The tunneling of electron is described by one dimensional quantum tunneling and its transmission coefficient. Sommerfeld model is used to derive the math expression of electron motion. Based on calculation results, we find that when the gap distance is below 1 nm, electron tunneling induced heat transfer starts to be considerable, which could exceed near-filed radiative heat transfer.

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