Fans and Blowers

PEMP<br /> RMD 2501<br /> <br /> Fans and Blowers<br /> Session delivered by:<br /> Prof. Q H<br /> Prof Q.H. Nagpurwala<br /> <br /> 06a<br /> <br /> © M.S. Ramaiah School of Advanced Studies<br /> <br /> 1<br /> <br /> Session Objectives<br /> <br /> PEMP<br /> RMD 2501<br /> <br /> This session is intended to discuss the following:<br /> <br /> • Types and working principle of fans and blowers<br /> • Applications of various fans and blowers<br /> • Pressure rise flow coefficient and efficiency<br /> rise,<br /> • Velocity triangles<br /> • Performance characteristics<br /> • Fan laws<br /> <br /> 06a<br /> <br /> © M.S. Ramaiah School of Advanced Studies<br /> <br /> 2<br /> <br /> What is a Fan?<br /> <br /> PEMP<br /> RMD 2501<br /> <br />  Any device that produces a current of air by the movement of<br /> broad surfaces can be called a fan.<br />  Fans fall under the general classification of “turbomachinery”<br /> turbomachinery<br /> and have a rotating impeller at least partially encased in a<br /> stationary housing.<br />  Fans are similar in many respects to pumps. Both are<br /> turbomachines that transfer energy to a flowing fluid. It is easy to<br /> distinguish between fans and pumps: pumps handle liquids; fans<br /> handle gasses.<br />  Broadly speaking, the function of a fan is to propel, displace, or<br /> move air or gas.<br /> 06a<br /> <br /> © © M.S. Ramaiah School of Advanced Studies<br /> M. S. Ramaiah School of Advanced Studies, Bangalore<br /> <br /> 3<br /> <br /> Fans, Blowers and Compressors<br /> <br /> PEMP<br /> RMD 2501<br /> <br /> Fans, bl<br /> F<br /> blowers and compressors are diff<br /> d<br /> differentiated b the method used to<br /> i d by h<br /> h d<br /> d<br /> move the air, and by the system pressure they must operate against.<br /> Difference Between Fans, Blower and Compressors<br /> Difference Between Fans Blower and Compressors<br /> Equipment<br /> <br /> Specific Ratio<br /> <br /> Pressure Rise (mmWC)<br /> <br /> Fans<br /> <br /> Up to 1.11<br /> Up to 1 11<br /> <br /> 1136<br /> <br /> Blowers <br /> <br /> 1.11 to 1.20<br /> <br /> 1136 to 2066<br /> <br /> Compressors<br /> <br /> More than <br /> More than<br /> 1.20<br /> <br /> As per American Society of Mechanical Engineers<br /> (ASME) the specific ratio – the ratio of the<br /> discharge pressure to the suction pressure – is used<br /> for defining the fans and blowers<br /> 06a<br /> <br /> © © M.S. Ramaiah School of Advanced Studies<br /> M. S. Ramaiah School of Advanced Studies, Bangalore<br /> <br /> 4<br /> <br /> Components of Fan/Blower System<br /> <br /> PEMP<br /> RMD 2501<br /> <br /> Turning Vanes<br /> (typically used on<br /> short radius elbows)<br /> Outlet Diff<br /> O tl t Diffusers<br /> <br /> Provide air for<br /> ventilation and<br /> industrial<br /> processes that<br /> need air flow<br /> Filter<br /> <br /> Heat<br /> Exchanger<br /> Baffles<br /> <br /> Inlet<br /> Vanes<br /> Motor<br /> Controller<br /> <br /> Centrifugal Fan/Blower<br /> Belt Drive<br /> <br /> 06a<br /> <br /> Variable Frequency Drive<br /> Motor<br /> <br /> © © M.S. Ramaiah School of Advanced Studies<br /> M. S. Ramaiah School of Advanced Studies, Bangalore<br /> <br /> 5<br /> <br />