Capillary Limits  
The capillary limit is also dependent on the heat pipe dianeter,length  pipe diameter, length, and orientation.Larger wick crosss-  sections for fluid flow and larger  vapor space cross-sections for  vapor flow ,which reduce frictional  losses resulting from the fluid and   vapor flow,respectively.As a  result,larger diameter heat pipes  will transport more power than smaller diameter heat pipes.Longer  
heat pipes will have larger frictional  losses as the fluid flows through  the wick structure and will transport   less power than shorter heat pipes.  heat pipes operating in a gravity-  aided orientation will transport more   power than heat pipes in a horizontal  orientation.Likewise a heat pipe in a   horizontal orientation will transport   more power than a heat pipe in an   against-gravity orientation.Chart C shows the capillary limit as a function  of temperature for a variety of heat   pipe diameters and a horizontal  orientation.For the same heat pipe,  Chart Dnshows the capillary  limit as a function of temperature  for various heat pipe diameters and   a vertical,gravity-aided orientation.  Chart E shows the capillary  limit as a function of temperature for  a variety of heat pipe lengths and a  horizontal orientation.