Method of operating a cooling apparatus to provide stable two-phase flow

A method operating a cooling apparatus to allow cooling lines extending from an inlet manifold to an outlet manifold to be safely added or removed during operation of the cooling apparatus without causing unstable two-phase flow, the method comprising:

• providing a cooling apparatus comprising:
• an inlet manifold;
• an outlet manifold;
• a bypass extending from the inlet manifold to the outlet manifold;
• and M connection ports on each of the inlet manifold and the outlet manifold to accommodate up to M cooling lines extending between the inlet manifold and the outlet manifold, wherein M is a variable, and wherein the bypass comprises a pressure regulator;
• providing a flow rate of single-phase liquid coolant to the inlet manifold;
• and
• setting the pressure regulator in the bypass to provide a flow rate through the bypass ({dot over (V)}bypass) of about (M×{dot over (V)}line)+(M−L)×{dot over (V)}line, wherein {dot over (V)}line is an average flow rate through each of the cooling lines, and wherein L is the actual number of cooling lines installed between the inlet manifold and the outlet manifold, L being equal to or less than M.

A method of selecting flow rates to provide stable operation within a cooling apparatus comprising two-phase bubbly flow, the method comprising:

• providing a cooling apparatus comprising:
• a primary cooling loop comprising:
• a pump configured to provide a flow rate of single-phase liquid coolant at a pump outlet;
• a reservoir fluidly connected to the cooling loop and located upstream of the pump and configured to store a supply of single-phase liquid coolant for the pump;
• one or more cooling lines fluidly connected to the primary cooling loop and extending between an inlet manifold and an outlet manifold, each cooling line fluidly connected to one or more heat sink modules, each heat sink module mounted on a heat-providing surface;
• a first bypass having a first end and a second end, the first end of the first bypass being fluidly connected to the primary cooling loop downstream of the pump outlet, the second end of the first bypass being fluidly connected to the primary cooling loop upstream of the reservoir and downstream of the heat sink modules, the first bypass comprising a first heat exchanger and a first pressure regulator, the first pressure regulator configured to regulate a first bypass flow rate of the flow rate of single-phase liquid coolant through the first heat exchanger, the first heat exchanger configured to subcool the first bypass flow rate of coolant below a saturation temperature of the coolant;
• and
• a second bypass having a first end and a second end, the first end of the second bypass being fluidly connected to the primary cooling loop downstream of the pump and downstream of the first end of the first bypass and upstream of the one or more heat sink modules, the second end of the second bypass being fluidly connected to the primary cooling loop downstream of the one or more heat sink modules and upstream of the reservoir, the second bypass comprising a second pressure regulator configured to regulate a second bypass flow rate of the single-phase liquid coolant through the second bypass;
• setting the second pressure regulator to provide a flow rate of about {dot over (V)}line through each of the cooling lines and to provide the second bypass flow rate about equal to L×{dot over (V)}line, wherein L is the number of cooling lines extending between the inlet manifold and the outlet manifold;
• and
• setting the first pressure regulator to provide the first bypass flow rate about equal to 2 L×{dot over (V)}line.