Flometrics Pistonless Rocket Pump FAQ

If a pistonless pump weighs more than a turbopump, how can it be better?

On a system level, the weight of the power source for the pump is very important. For a turbopump in a typical first stage the propellant required to run the pump weighs 5 times more than the pump itself. The residual propellants that must be left in the tank to prevent cavitation often weigh more than the turbopump. Although the propellants are very energetic, the turbopump must run on a very rich mixture to prevent overheating. This results in low fuel economy for the turbopump. The pistonless pump runs on helium, which is much lighter than propellant. The pistonless pump system includes the pump, the helium and the helium tank. The total system weight is similar to the turbopump plus the turbopump fuel. A pistonless pump system that runs on liquid helium which is heated at the engine is much lighter than a turbopump system. Therefore the pistonless pump system has equivalent or better performance to a turbopump system, at a much lower cost. For details, see the 2003 and 2004 papers

What about testing the pistonless pump with a rocket engine?

We have tested the pump with an Altlas Vernier engine. Most liquid fueled rocket engines are initially tested with a pressure fed system. The pistonless pump acts like a pressure fed system as far as the engine is concerned, so the amount of testing required to migrate to a pump fed system is minimal. For example, the pistonless pump uses no energy to maintain pressure, so the engine start timing does not have to be synchronized with the pump. Contrast this with a turbopump powered engine, where the pump/engine combination requires extensive testing, modeling and tuning to get the engine to start and run smoothly.

What about the pressure fluctuations?

New valves have been designed and tested that reduce the pressure fluctuations to .4% (average deviation) of the output pressure. The valve designs are constantly being updated to increase reliability and reduce weight and cost. (graphs and data are available)

All liquid rocket engines transmit vibrations to the propellant tanks, which result in pressure fluctuations. Most turbopump-powered vehicles have anti-pogo devices which reduce pressure fluctuations, and these will probably not be needed in a system which uses the pistonless pump because the tank pressure is decoupled from the pump output pressure.

Most liquid fueled rockets, even manned ones, live with a little bit of pogo, which is associated with pressure fluctuations in the engine. The pistonless pump isolates the pressure in the tank from the engine, so it reduces the chance for pogo.

Who is funding this project?

Flometrics has been in business since 1993, providing engineering services to a wide range of clients. This project is entirely self-funded so we are limited in the amount of testing and development that we can do. No government or venture funding has been used, although some pump development has been funded by RocketPlane and Masten Space Systems.

Why hasn’t this been tried before?

All of today’s launch vehicles are derivatives of ICBM’s developed under a rush schedule during the Cold war. Since the V2 used a turbopump, that was considered to be a low risk solution. Alternatives have been looked at, but the turbopump is well known, and appears simple on Powerpoint diagrams. The pistonless pump idea has been around for quite a while, but until now it has not been fully developed, analyzed or tested.

A good parallel is electronic fuel injection which is standard on all cars today, but debuted on a production car in 1957 (AMC Rambler Rebel Special Edition).

What is the TRL (technology readiness level) of the pump?

The pump is at TRL 4, we have tested it in a lab and with a rocket engine. A plastic demo model has been developed that has been run at conferences for hours on end. Flightweight, mass producible designs have been developed and vendors for the welding and machining have been identified. Manufacturing the pump will be straightforward, and there are no technological barriers to overcome in its development. Right now development is based on customer needs. What is TRL?

What propellants can it be used with?

It has been used with water, kerosene and liquid nitrogen. A stainless steel pump using Teflon valve seals could pump any common rocket fuel including hydrocarbons, LOX, H2O2, hydrazine, NTO, etc. Liquid Hydrogen pumps are feasible as well. The pump can also use vaporized propellant as the driving gas.

Why does Flometrics think they can make this pump work?

We have developed a number of products and helped them get to market. We have designed parts for an infusion pump, excimer laser, Oxygen concentrator, and a UAV cooling system that are all currently being sold. We know how to take an idea, turn it into a prototype, develop manufacturing, test and quality processes, ship the product and support it. We are not just PowerPoint engineers who rarely get beyond the design study stage or tinkerers who spend all their time in the shop and never crunch any numbers. We make money selling engineering services to repeat customers and we see designing, building and selling rocket fuel pumps as a natural extension of our current work.

How does the pump scale up?

Design studies have been completed for pumps for vehicles up to the million lb thrust level. Pumps have been built and tested 6 to 16 inches in diameter with similar performance and they work according to predictions.

What does NASA think?

Last year's SBIR proposal got positive reviews, although it was not funded. We will see how it goes this year. Email if you would like to see a copy of their endorsement.

Specifications Flometrics Pistonless Pump

Call or email Flometrics today for a free application study, including pump weight and size for your vehicle or thrust chamber.

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