渐缩喷管在设计工况下工作（ p 2 = pb ），如果喷管进口截面参数及背压保持不变，那么将此喷管截掉一段，其出口流速和流量将按（  ）变化。

A、<span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: " times="" new="" roman";="" mso-hansi-font-family:="" "times="" mso-bidi-font-family:="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">流速减小，流量增加</span>

B、<span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: " times="" new="" roman";="" mso-hansi-font-family:="" "times="" mso-bidi-font-family:="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">流速、流量都减小</span>

C、<span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: " times="" new="" roman";="" mso-hansi-font-family:="" "times="" mso-bidi-font-family:="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">流速不变，流量增加</span>

D、<span style="FONT-FAMILY: 宋体; FONT-SIZE: 12pt; mso-ascii-font-family: " times="" new="" roman";="" mso-hansi-font-family:="" "times="" mso-bidi-font-family:="" mso-font-kerning:="" 1.0pt;="" mso-ansi-language:="" en-us;="" mso-fareast-language:="" zh-cn;="" mso-bidi-language:="" ar-sa"="">流速减小，流量不变</span>