渦卷式壓縮機渦卷之應力與變形分析

Abstract

本文使用擎宇國際股份有限公司所提供之渦卷尺寸，並且以該廠商所提供之渦卷運轉時內部之冷媒壓力和進出口溫度，以Solidworks等商用軟體進行模擬分析。本文之壓縮機主要針對空調系統所需之冷凍能力為24噸之壓縮機。在本文模擬中，渦卷所使用之材料為鑄鐵與鋁合金，並針對渦卷運轉週期中受力最大之瞬間，其實際情況之溫度、冷媒壓力，以及渦卷所受之拘束條件，作有限元素分析。 由模擬結果得知，溫度梯度才是造成渦卷產生應力及變形的主因，在渦卷中心的高溫區產生最大之應力與變形，偏心軸之推力與冷媒壓力所產生之力矩造成渦卷之翻轉。鑄鐵渦卷所受之拉應力與壓應力與材料極限應力均有一段差距，可視為一安全之設計；而鋁合金渦卷則因為所得之應力值已接近降伏強度，安全係數過低，尺寸設計上應增加厚度。

An analysis was made for a scroll type compressor with 24-ton freezing capacity, used in air conditioning systems. In the simulation, the finite element method was employed. The scroll was assumed to be made of gray cast iron and aluminum alloy, respectively. It was also assumed that the scroll was subjected to the maximum pressure and the temperature in an extreme condition. The results showed that the temperature gradient was the main cause of high stresses and severe deformation occurring in the scroll. The maximum stresses and deformation were at the center of the scroll. The pushing force of eccentric shaft couple with the refrigerant pressure made the scroll overturn. The tensile stresses and the compressive stresses of the gray cast iron scroll were lower than the ultimate strength of the gray cast iron. So it could be regard as a safety design. However, the maximum stress in the aluminum-alloyed scroll was closed to the yield strength of the alloy. Therefore, the thickness of the scroll blade should be increased suitably.