Make an angular turn. Divide carbon steel elbows, cast steel elbows, alloy steel elbows, stainless steel elbows, copper elbows, aluminum alloy elbows, etc. by material. The elbow can be said to be used in all walks of life across the country, from small families to large enterprises. Each elbow has its own advantages and uses, sincerely welcome new and old friends to come and buy. Stainless steel elbow is a commonly used connection pipe fitting in pipeline installation, which is used to connect the pipe bend. Other names: 90 degree elbow, right angle bend, love and bend, etc. Wear-resistant elbows can be favored by the market and continue to replace some traditional anti-wear materials. The fundamental reason lies in its excellent product quality and its compatibility with traditional anti-wear materials. In order to obtain the effect of the upstream elbow installation conditions on the performance of the inner cone flowmeter and the required shortest straight pipe length, numerical simulation of computational fluid dynamics was applied to the inner cone flow rate of 100 mm diameter and equivalent diameter ratio 0.45/0.65/0.85. The project carried out a simulation study of the upstream single 90° elbow. The simulation medium is water at room temperature, and the Reynolds number ranges from 0.498×105 to 4.98×105. The research plan is divided into two types: baseline and upstream single 90° elbow, a total of 15 groups. Using the relative error of the average outflow coefficient and the additional uncertainty as the main evaluation criteria of the installation conditions, the length of the straight pipe section of a single 90° elbow in the upstream is given and compared with the conclusions of foreign studies.