压强差△p，密度ρ，长度l，流量Q的无量纲集合是：<br/> A、<img src="https://static.zxtiku.com/wangke/imgs/topic/3af58fcc2a0b6ba71a9076b5439150f0.jpg"/><br/> B、<img src="https://static.zxtiku.com/wangke/imgs/topic/2bcb1f06a1d7a44e6f5be36c83945249.jpg"/><br/> C、<img src="https://static.zxtiku.com/wangke/imgs/topic/e2af3061a0354daceb716a8731e9f202.jpg"/><br/> D、<img src="https://static.zxtiku.com/wangke/imgs/topic/5aee14a228d1b8f9594dbd2397576b42.jpg"/>