I NDEX SR NO. 1} 2} 3} 4} 5} 6} 7} 8} 9} 10} 11} 12} 13} 14} TOPI CS I NTRODUCTI ON NECESSI TY DUAL PI STONLESS PUM P WORKI NG OF THE PUM P DI AGRAM OF PI STONLESS PUM P ADVANTAGES APPLI CATI ONS PERFORM ANCE VALI DATI ON I STALLATI ON I N ROCKET WORKI NG M ODELOF THE PUM P GRAPH OF FLOW RATE VS. TI M E DI SADVANTAGES COCLUSI ON BI BLOGRAPHY

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.

I NTRODUCTI ON:
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.

NECESSECI TY: 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.
THE DUAL PI STONLESS PUM P:

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.
WORKI NG:

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.

PI STONLESS PUM P FI GURE:

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.

ADVANTAGES:

Nearly all of the hardware in this pump consists of pressure vessels, so the weight is low.There are less than 10 moving parts , and no lubrication issues which might cause problems with other pumps. The design and constr. Of this pump is st, forward and no precision parts are required .This device has advantage over std.

turbopumps in that the wt. is about the same, the unit,engg.and test costs are less and the chance for catastrophic failure is less.This

pump has the advantage over pressure fed designs in that the wt. of the complete rocket is much less, and the rocket is much safer because the tanks of rocket fuel do not need to be at high pressure.the pump could be started after being stored for an extended period with high reliability.It can be used to replace turbopumps for rocket booster opn. or it can be used to replace high pressure tanks for deep space propulsion.It can also be used for satellite orbit changes and station keeping.

APPLI CATI ONS: 1}DEEP SPACE PROPULSI ON: 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 PRI ZE VEHI CLE FUEL PUM P APPLI CATI ON: 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.

PERFORM ANCE VALI DATI ON:

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.

I NSTALLATI ON FI GURE:

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.

WORKI NG M ODEL OF ROCKET FUEL PUM P:

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 PUM P:

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

DI SADVANTAGES: 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.

CONCLUSI ON: 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 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.

BI BLOGRAPHY: 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)