可裝卸式水上腳踏車之概念設計與性能分析之研究

Abstract

本研究主要目的在於提出適用於一般腳踏車可拆卸載具之概念設計，可使之組裝為水上腳踏車。因此如何設計載具之浮具、傳動系統、轉向機制與裝卸腳踏車之夾具為一重要課題。本研究使用繪圖軟體Solidworks進行載具外型與設備位置佈置，以預估整體重量、重心與浮心位置，藉由設備位置佈置，可調整重心與浮心位置，使船體在靜態平衡時可平浮於水面上。 本研究採用流體分析軟體ANSYS-FLUENT，進行載具於自由液面(Free Surface)航行之阻力估算驗證與計算，搭配使用RANS(Reynolds Average Navier – Stokes equations) 描述流場狀態，紊流模型使用Realizable κ-ε搭配壁面函數(Wall function)，求解方法採用SIMPLE (Semi-Implicit Method for Pressure-Linked Equations)。 透過FLUENT模擬可得船體在固定姿勢下之阻力模擬結果與文獻實驗趨勢一致，確認以FLUENT模擬計算船體於水面航行之流體動力分析的可行性。藉由阻力性能分析之結果與螺槳效率預估載具的航行速度，當人力提供之功率為300 Watt時，載具之航行速度可達時速8.6公里。

The purpose of the present study is to develop a concept design of a detachable bicycle boat and analyze its performance. The key issues are focused on the design of the floats, transmission system, steering system and setting mechanism as well as the performance analysis. The graphics software SOLIDWORKS is applied to design configuration and to estimate the overall weight, center of gravity and center of buoyancy. The computational fluid dynamics software ANSYS-FLUENT is applied to simulate the free surface viscous flow field of the vehicle, and to calculate its hydrodynamic coefficients. The governing equations for these simulations are RANS (Reynolds – Average Navier – Stokes equations), while realizable κ-ε model with wall function is adopted as a turbulent model. The solver used is SIMPLE (Semi-Implicit Method for Pressure-Linked Equations). Firstly, the CFD simulation process is validated by comparing with the existing experimental data. Then the resistance of the present vehicle is determined by applying similar CFD simulation process. The results of the resistance analysis combining with proper estimation of propulsion efficiency show that the proposed detachable bicycle boat may reach a speed of 8.6 kilometers per hour for a man with power output of 300 W, which is about the average of human power of a young man.