INTRODUCTION:

NASA have developed a Low cost rocket fuel pump which has

Comparable performance to turbopump at 80-90% lower cost. Perhaps

the most difficult barrier to entry in the liquid rocket business is the

turbo pump. A turbo pump design requires a large engineering effort

and is expensive to mfg. and test. Starting a turbo pump fed rocket

engine is a complex process, requiring a careful of many valves and

subsystems.In fact ,Beal aerospace tried to avoid the issue entirely by

building a huge pressure feed booster. Their booster never flew, but the

engineering behind it was sound and ,if they had a low cost pump at

their disposal ,they might be competing against Boeing. This pump

saves up to 90% of the mass of the tanks as compared to a pressure fed

system. This pump has really proved to be a boon for rockets . By this pump

the rocket does not have to carry heavy load and can travel with very high

speed.

NECESSECITY:

The turbo pumps used in rocket are very heavy,containing many

rotating parts by which there are more frictional losses which more

consumption of fuel there by decreasing the efficiency of the engine .Also,

the maintainanace of such pump is, very important factor since the rocket

has to remain stable in the space, is difficult and require complex methods

for it. If this pump gets any fault then its repairance requires long time and

also it is avery hectic task.So, there must be such a device which

overcomes all the drawbacks of the turbopump as above. The

pistonless pump is the solution for the problems faced by using

turbopumps. They have only a drawback that they supply fuel with less

pressure as compared to turbopumps.

DESCRIPTION

The pistonless pump is similar to a pressure fed system, but instead of

having the a main tank at high pressure (typically 300-500 psi) the proposed

pump system has a low pressure tank (5 -50 psi) which delivers propellant at

low pressure into a pump chamber, where it is then pressurized to high

pressure and delivered to the engine. A diagram of the pump operation is

shown in Figure 1. Two pumping chambers are used in each pump, each one

being alternately refilled and pressurized. The pump starts with both

chambers filled (Step 0, not shown). One chamber is pressurized, and fluid is

delivered to the rocket engine from that chamber(Step 1). Once the level gets

low in one chamber, (Step 1a) the other chamber is pressurized; and flow is

thereby established from both sides during a short transient period(Step 2)

until full flow is established from the other chamber. Then the nearly empty

chamber is vented and refilled. (Step 3) Finally the cycle repeats. This

results in steady flow and pressure. The pump is powered by pressurized gas

which acts directly on the fluid. Initial tests showed pressure spikes as the

pump transitioned from one chamber to the other, but these have since been

eliminated by adjusting the valve timing. For more details on the pump and a

discussion of the second-generation design see reference 1 or 8. This pump

is more robust than a piston pump in that it has no high pressure sliding

seals, and it is much less expensive and time consuming to design than a

turbopump and a system which uses the pump has far lower dry mass and

unusable residuals than turbopumps do.

THE DUAL PISTONLESS PUMP:

NASA has designed,built and tested a simple, light weight pump

(dual pistomless pump) for use in liquid propelled rocket where a

reliable pump with minimal moving parts is needed. This pump has the

potential to reduce the cost and increase the reliability of rocket fuel pumps

by a factor of 20 to 100.

WORKING:

Rocket engines requires a tremendous amount of fuel high

at high pressure .Often th pump costs more than the thrust

chamber.One way to supply fuel is to use the expensive

turbopump mentioned above,another way is to pressurize fuel

tank. Pressurizing a large fuel tank requires a heavy , expensive

tank. However suppose instead of pressurizing entire tank, the

main tank is drained into a small pump chamber which is then

pressurized. To achieve steady flow, the pump system consists of

two pump chambers such that each one supplies fuel for ½ of

each cycle. The pump is powered by pressurized gas which acts

directly on fluid. For each half of the pump system, a chamber is

filled from the main tank under low pressure and at a high flow

rate, then the chamber is pressurized, and then the fluid is

delivered to the engine at a moderate flow rate under high

pressure. The chamber is then vented and cycle repeats. The

system is designed so that the inlet flow rate is higher than the

outlet flow rate.This allows time for one chamber to be vented ,

refilled and pressurized while the other is being emptied.A bread

board pump has been tested and it works great .A high version

has been designed and built and is pumping at 20 gpm and 550psi.

WORKING CYCLE

PISTONLESS PUMP FIGURE:

As shown in the above diagram , two cylinders are there ,

filled with the fuel from the main tank. This main tank is emptied

in these two cylinders, these cylinders are pressurized by the high

pressure tank,as shown.The high pressure tank pressurizes one

cylinder of high pressure,as shown,as soon as the cylinder is

emptied , it is vented, again it gets filled up from the main tank.The

same cycle reapeats for the second cylinder.the cycle is such that,

fuel is supplied by the cylinder one by one.ie. each cylinder

supplies fuel for each half cycle.As one cylinder supplies the fuel

other has enough time to refill.

APPLICATIONS:

DEEP SPACE PROPULSION :

NASA has a need for high power propulsion to land and

spacecraft on the moons of Jupitor and beyond.this pump would

allow these missions to go forward due to lower weight of the fuel

tanks. For example, to land on Europa with a hydrazine

monopropellant rocket , pump fed design would save 80% of the

tank weight compared to a pump fed design.Further weight

savings could be achieved by heating the pressurant gas more,

because the pressurant would not be in contact with the propellant

for more than a few seconds . In addition ,the chamber could be

increased , saving engine weight and improving performance.

2. X PRIZE VEHICLE FUEL PUMP APPLICATION:

For X-prize competitors, a the fuel pump will reduce the cost

and increase the safety and reliability of their amateur manned

vehicles.Sitting on top of tons of rocket fuel is dangerous

enough,siiting on top if tons of rocket fuel at high pressure is

even more so. Many of the competitors plan to use Hydrogen

Peroxide(HTP) and jet fuel to power their rockets.When the

pump is used to pump HTP, it can decompose some of the fuel in

a gas generator to run the pump. This saves a considerable

amount of weight pressurant and main tankage.

In addition , the factor on the low pressure tanks will be similar to the

cost of the high pressure tanks alone.

PERFORMANCE VALIDATION:

A calculation of the weight of this type of pump shows that the

power to weight ratio would be dominated by the pressure chamber

and that it would be of the order of 8-12 hp per lb., for a 5 second

cycle using a composite chamber. This performance is similar to

state of the art gas-generator turbopump technology. (The F1

turbopump on the Saturn V put out 20 hp/lb) This pump could be

run until dry, so it would achieve better residual propellant

scavenging than a turbopump. This system would require a supply

of gaseous or liquid Helium which would be heated by a heat

exchanger mounted on the combustion chamber before it was used

to pressurize the fuel, as in the Ariane rocket.. The volume of gas required

would be equivalent to a standard pressure fed design, with a small

additional amount to account for ullage in the pump chambers. The rocket

engine itself could be a primarily ablative design, as in the NASA Fastrac,

scorpious rocket or in recent rocket engine tests.

INSTALLATION FIGURE:

A proof of concept model of the pump has been constructed out of

clear plastic and tested at low pressure. The results of the test are shown

below.The pressure and flow are quite steady. The pump system is run with

a Labview based computer program. There are two floats which are used to

monitor the level in each pump chamber and each chamber uses a two

solenoid valves, one to pressurize source and on to vent the chamber. The

installation figure of the pistonless pump is shown in the above figure. The

high pressure cylinder used for pressurizing fuel,is installed at the bottom of

the rocket,shown in green colour in the figure.And above this cylinder

further assembly is mounted as shown in the first diegram. Thus the figure

shows that the installation is very easy as compared to that of the turbo

pump.

WORKING MODEL OF ROCKET FUEL PUMP:

The pump shown is equipped with electronic level sensors and air

cylinder actuated ball valves. The pump works as predicted and it will be

easy to reconfigure it to pump LOX and jet fuel.this type of pump will make

rocket propulsion systems much more reliable and less expensive than that

of the turbo jet pump.

FLOW AND PRESSURE DATA FOR ROCKET FUEL PUMP:

The above graph shows the variation of the flow of fuel through

both of the cylinders .It shows that as one cylinder gets emptied the

other one gets filled up and fuel is supplied by each cylinder to

the engine for each half cycle. As one cylinder gets emptied the

other one gets filled up , thus giving an uninterrupted fuel supply

to the engine. Also, the time required for the refill of the fuel in

the cynlinder is sufficient to supply fuel for next half cycle.

A video of the pump in action is also available.The is steady as

well and as the design is improved, the flow and pressure will be

steadier. This pump is similar to one mentioned in 1960 in

Exploring the Solar System by Felix Godwin p-21 p-22 and to one

patented by Sobey,(3,213,804) Jim Blackmon and Eric Lanning

(6,314,978) A second generation version (patent pending) that is

lower in weight (12 hp/lb) has been designed and built and is now

being tested. The first prototype is designed to work with our Atlas

Vernier. It provides 20 GPM at 600+ psi and it is made of stainless

steel and Teflon to be compatible with all common rocket

fuels(LOX,RP-1, H2O2, hydrazine etc). Check this page soon for

test results. We plan to build a couple of flight ready versions of

this pump to pump LOX and kerosene and fly it on one of our

Atlas vernier powered rockets This rocket will be able to acheive an

altitude of over 100 miles

ADVANTAGES:

Safety:

• Negligible chance of catastrophic failure because typical failure

modes are benign.

• Leaks from the main tank involve lower pressures, coarser

atomization, and lower explosion hazards than from high pressure

propellants

• Easy to start up and shut down, similar to pressure fed systems. No

spool up time required.

• Thrust can be modulated quickly, to steer, rendezvous, or reduce

start/stop transient loads

• The pump can be run dry with no adverse effects. The pump can even

purge the lines leading to the engine.

• Minimal pogo effect as tank pressure is decoupled from engine

pressure.

• The pump is failure tolerant. A small leak in one of the check valves

will only increase the pressurant consumption of the pump, it will not

cause a pump failure. Software can be designed to keep a pump with

redundant valves and sensors operational, despite failed sensors or

valves.

• Unlike other pumps, no problems with seals, cavitation, whirl or

bearings.

Reliability:

• Check valves, level sensors and pneumatic valves can be made

redundant if necessary. The check valves in particular can be made

very reliable, while the pressurant supply and vent valves are small

enough to allow redundancy. All these components are currently

available as space qualified COTS components.

• The gas and liquid valves are only required to operate for about 100-

1000 cycles, so the valves would not be subject to significant wear.

• No sliding parts, no lubrication, may be started after being stored for a

long time.

• Not susceptible to contamination. Our prototype has been sitting in a

rusty steel tank for a year and it still works fine.

• The pump can be started after being stored for an extended period

with high reliability because it can use valves which have already

been flight qualified.

• The pump can also be vented to a low pressure so as to reduce loads

on propellant valves with seals subject to creep or degradation for

long duration space flights.

• Overall vehicle reliability in emergencies should improve, because

pump chambers allow limited propellant storage near the engines, that

can be used even if upstream feedlines are damaged.

Performance:

• It can be installed in the propellant tank to minimize vehicle size. Will

not reduce volume of propellant tanks because pump chambers hold

displaced propellant.

• Allow for design flexibility, arbitrarily shaped tanks can be located to

control CG

• For application in a weightless environment, the pump can be

designed to have at least one chamber full at engine cutoff, thereby

allowing for zero G restart with the propellant in the pump chamber

providing the ullage thrust. This means that the propellant settling

maneuvers and propellant control devices in the main tank are not

required.

• The pump also allows for efficient motor throttling with a response

time on the order of the pump cycle time, that is 2-5 seconds, with

much faster thrust ramp-up with a full chamber (<0.1 second if

desired), and tail-off, if it is acceptable to waste a modest amount of

pressurant). The pump works well at flow rates from zero to full flow,

so it can be used to provide pressurized propellant for attitude control

• If the pump is combined with an injector which can be partially shut

down, very deep throttling can be achieved.

• The pump vent gas can provide roll control or be diffused and/or

vented to both sides of the vehicle to minimize inadvertent application

of thrust. The fraction of the pump gas vented at high pressure is more

than enough to pressurize the main tank, for tank pressures less than

roughly 1/3 of pump discharge pressure).

DISADVANTAGES:

The pistonless pumps has disadvantages along

with such fine advantages.

1.They cannot pump to higher pressure than drive gas (area ratio is 1:1)

2.They cannot use either a staged combustion or expander cycle.

3.A gas generator cycle is also difficult to integrate with the pistonless

pump.

4.The generated gas must be chemically compatible with both the

propellants.

5.This gas generator lowers the Ignition start period of the engine.

CONCLUSION:

The most significance of property of Pistonless pump that makes

them different from that of turbo pump ,is the absence of piston.

This is the most unique technique.In this ,no. of rotating

parts is very less as compared to that of turbopump. Also, it’s installation is

very easy.and moreover, it is light weight than turbo pump.So, it has less

losses and improves,rather increases efficiency of engine.Also, it is much

economical than turbopump.

The only drawback of pistonless pump is that, that it cannot

supply high pressure fuel and also,it cannot have stage combustion or

expander cycle,further, it has no vibrations.

BIBLOGRAPHY:

1}Theory Of Rocket propulsion (By R.H.Boden)

2}Book Of Rocket Propulsion (By zechosloviky)

3}Mechanics Of Thermodynamics Of propulsion

(By Philip Hill,Call Peterson)

4}http :// www . kahuna . sdsu . edu

5}www . flowmetrics . com

6}www.xcor.com

INDEX

SR NO. TOPICS PAGE NO.

1} INTRODUCTION 1

2} NECESSITY 2

3} DUAL PISTONLESS PUMP 2

4} WORKING OF THE PUMP 3

5} DIAGRAM OF PISTONLESS PUMP 4

6} ADVANTAGES 6

7} APPLICATIONS 7-8

8} PERFORMANCE VALIDATION 9

9} ISTALLATION IN ROCKET 10-11

10} WORKING MODELOF THE PUMP 12-13

11} GRAPH OF FLOW RATE VS. TIME 14-15

12} DISADVANTAGES 16

13} COCLUSION 17

14} BIBLOGRAPHY 18

ABSTRACT:

Pistonless pump for rocket has been proved to be the most

economical than piston pump or turbopump.

In pistonless pumps, piston is absent. It has very much less

rotating parts than that of piston pumps or turbo pumps. So, it has less

friction losses and there by it helps to improve the efficiency of the engine

considerably.They can be easily installed in the rocket than

turbopumps.Also,it reduces the weight of rocket.

This article discusses the working , advantages of pistonless

pump over turbopump.

Pistonless pumps are 80-90% economical than that of

piston pump or turbo pumps.Nasa has manufactured such kind of pump and

tested it actually,and they found it works conveneiently.