Momentum transfer using liquid injection

An apparatus for controlling flow rate of a gas stream, the apparatus comprising

• a chamber configured to contain a gas, the chamber having a gas inlet to deliver the gas into the chamber and a gas outlet to convey the gas out of the chamber, a gas flow through the chamber characterized by a downstream direction from the gas inlet to the gas outlet and an upstream direction from the gas outlet to the gas inlet;
• an inner wall separating the gas inlet from the gas outlet, the inner wall having a first gap and a second gap, the first and second gaps providing for the only fluidic communication between the gas inlet and gas outlet;
• a first liquid source configured to deliver a first liquid at a first pressure greater than 500 psi;
• a first injector coupled to the chamber and the first liquid source, and configured to spray the first liquid into the chamber through the first gap at a first velocity that imparts a downstream momentum to the gas in the chamber, the first injector including a first nozzle having:
• a first orifice having a first size that does not exceed 0.01 square inches of orifice area;
• and
• a first shape configured to generate a spray of droplets of liquid;
• a second injector coupled to the chamber and configured to spray a second liquid into the chamber through the second gap at a second velocity that imparts an upstream momentum to the gas in the chamber;
• a sensor coupled to at least one of the chamber, the first injector, and the second injector, the sensor configured to measure a control parameter of the gas flow through the chamber;
• and
• a controller coupled to the sensor and at least one of the first and second injectors, the controller configured to receive the control parameter and adjust at least one of the first velocity of the first liquid sprayed from the first injector and the second velocity of the second liquid sprayed from the second injector in response to the received control parameter.