The effects of the velocity gradient and wall-proximity on the measuring errors are related to the flow direction.

近壁对总压测量影响不大。速度梯度和近壁对测量误差的影响还与来流方向有关。

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This paper analyzes air source in heating system, states that gas is harmful in the system, points out level pipe gradient being small in single measure system, and velocity of flow must keep great.

本文通过分析采暖系统中的空气的来源，提出空气在系统中的危害，针对单户计量系统中水平管坡度较小，提出水平支管中水流速应保持较大。

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In addition, the present direct integral method can be used to evaluate the velocity distribution for external flow field correctly where the method of gradient cannot be used at all.

此外，直接积分法还可正确地计算外部流场速度分布。这是偶强梯度法不能完成的。

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