Experimental evaluation of rational parameters of pre-acceleration to ensure liquid sustainer engine launch in zero gravity

2019 ◽  
Author(s):  
V.B. Sapozhnikov ◽  
A.R. Polyanskiy ◽  
A.V. Korolkov
Keyword(s):  
Experimental Studies ◽  
Free Fall ◽  
Bond Number ◽  
Zero Gravity ◽  
Load Pulse ◽  
Deposition Processes ◽  
Suborbital Flight ◽  
Liquid Rocket ◽  
Time Required ◽  
Fuel Deposition

The paper presents the results of experimental studies of liquid fuel deposition processes in liquid rocket propulsion system tanks under the conditions of free, i.e. unperturbed, orbital and suborbital flight under the influence of small prestart G-load created by auxiliary engines before liquid sustainer engine launch. Having conducted the dimension analysis, we formed the structure of dimensionless groups, which determine the dependence of the time required for fuel deposition to the tank intake, on the g level, the degree of tank filling and the physical properties of the propellant. Experimental studies were carried out on a zero gravity test bench, using the principle of implementing below-G conditions at the free fall of the equipment under test, and on a laboratory aircraft at the "Kepler's parabola" flight. The results of experimental studies have shown that the effect of viscosity on the deposition rate is practically absent. At the same time, in experiments it was found that, starting with Bond numbers exceeding 40 ... 50, the dimensionless separation time does not depend on Bond number, the value of the latter being determined by the minimum radius of free gas inclusions, deformed during when ascending during the separation process. Findings of research show that with a considerable duration of the prestart G load pulse, the movement of gas bubbles in the liquid under the action of a G load pulse becomes quasistationary.

Calculation of minimum supply of fuel in contact with the innertank device to ensure the operation of a liquid-propellant rocket engine in zero gravity

2021 ◽  
Author(s):  
V.B. Sapozhnikov ◽  
A.R. Polyanskiy ◽  
A.V. Korolkov
Keyword(s):  
Relaxation Time ◽  
Liquid Fuel ◽  
Rocket Engine ◽  
Design Stage ◽  
Zero Gravity ◽  
Liquid Propellant ◽  
Liquid Propellant Rocket Engine ◽  
Suborbital Flight ◽  
Fuel Deposition ◽  
Propellant Rocket

The paper introduces the results of theoretical studies of the process of liquid fuel deposition in liquid-propellant rocket engine tanks under conditions of free (undisturbed) orbital (suborbital) flight under the influence of a small pre-launch overload created by auxiliary engines before the liquid-propellant sustainer starting. In this work, we estimated the relaxation time of the free volume of liquid for the most unfavorable case, and the minimum supply of the covolume for the guaranteed starting and uninterrupted operation of the liquid-propellant rocket engine in zero gravity. Furthermore, we investigated the possibility of controlling the relaxation time with a gradual or stepwise starting operation. The proposed formula makes it possible at the design stage to assess the minimum supply of fuel, which can be in contact with the innertank device before starting the liquid-propellant sustainer in zero gravity in order to ensure the uninterrupted operation of the propulsion system.

Experimental estimation of residual propellant in the fuel tanks with innertank capillary devices for spacecraft propulsion systems

2019 ◽  
Author(s):  
V.B. Sapozhnikov ◽  
A.R. Polyanskiy ◽  
A.V. Korolkov ◽  
S.B. Konstantinov ◽  
L.G. Alexandrov
Keyword(s):  
Complex Structure ◽  
Experimental Studies ◽  
Free Fall ◽  
Propulsion Systems ◽  
Rocket Propulsion ◽  
Criterion Equation ◽  
Fuel Tanks ◽  
Liquid Rocket Propulsion ◽  
Liquid Rocket

The paper presents the results of experimental studies of the processes of emptying the fuel tanks of spacecraft liquid rocket propulsion systems at the final stages of free (undisturbed) flight in tanks with innertank capillary devices (IT CD). On the basis of the analysis of the emptying process, the dimensionless complex structure is formed. The complexes determine the dependence of the residual propellant on the physical properties of the propellant and the parameters of the IT CD. Experimental studies were performed on the weightlessness stand, using the principle of realization of the conditions of reduced weight in tested equipment free fall. The results of the experimental studies have shown that the main criterion determining the value of residual propellant is the Froude number. The criterion equation for determination of residual propellant is obtained. The influence of viscosity and surface tension of the propellant on the value of residual propellant begins to affect at the values of the Froude numbers exceeding 104.

Cooling of Fruit with Arbitrary Shape: Simulation Using Galerkin-Based Integral Method

2017 ◽  
Vol 10 ◽  
pp. 1-15
Author(s):  
P. Morais Pessôa ◽  
A.G. Barbosa de Lima ◽  
R. Swarnakar ◽  
J.P. Gomes ◽  
W.M.P. Barbosa de Lima
Keyword(s):  
Integral Method ◽  
Arbitrary Shape ◽  
Heat Conduction Equation ◽  
Low Cost ◽  
Experimental Studies ◽  
Volume Ratio ◽  
Transient Heat Conduction ◽  
Cooling Time ◽  
Time Required ◽  
Kinetics Of

Cooling has been used for the preservation of fresh produce such as fruit and vegetables due to its low cost and high effectiveness in maintaining the product quality. Recently, several researchers have conducted theoretical and experimental studies for obtaining the kinetics of cooling and cooling time for fruits with different geometries. Present work, therefore, aims to simulate the cooling of fruits with particular reference to banana, orange, strawberry and Tahiti lemon. The transient heat conduction equation and its analytical solution using Galerkin based integral method are presented. It has been found that the strawberry has lower dimensionless cooling time compared with time required to cool other fruits, which is due to its higher surface area/volume ratio value. In orange and lemon the temperature distribution was found to be homogeneous in the angular direction, while in banana and strawberry it was two-dimensional due to shape of the fruits.

Pretreatment processes for membrane filtration of raw water containing manganese

2001 ◽  
Vol 1 (5-6) ◽  
pp. 341-348 ◽  
Author(s):  
S. Takizawa ◽  
L. Fu ◽  
N. Pradhan ◽  
T. Ike ◽  
M. Ohtaki ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Manganese Concentration ◽  
Fluidised Bed ◽  
Raw Water ◽  
Biological Pretreatment ◽  
Manganese Removal ◽  
Time Required

Experimental studies on chemical and biological pretreatments in membrane filtration processes were carried out to removal manganese contained in raw water and to prevent membrane fouling due to manganese. Two types of the pretreatment reactors, i.e. the fluidised-bed and fixed-bed configurations, were compared in the biological pretreatment experiments. New synthetic media (tubular polypropylene, I.D. 3 mm, O.D. 4 mm, length 5 mm) were used in all three experiments as a manganese-oxidising catalyst. The chemical pretreatment using sodium hypochlorite was effective in manganese removal and controlling membrane fouling; more than 0.8 mg-Cl2/L of chlorine dose was necessary to bring the manganese concentration from 0.4 mg/L in raw water to less than 0.05 mg/L. The biological pretreatment for manganese removal required a long start-up period of more than 40 days. The fixed-bed biological pretreatment was superior in manganese removal and in control of membrane fouling to the fluidised-bed biological pretreatment, which showed wash-out of the attached bacteria resulting in membrane fouling. The linear velocity and the empty-bed retention time required for the treatment of 0.14 mg-Mn/L in the fixed-bed biological pretreatment was 206 m/d and 8.0 minutes, respectively.

Experimental Studies of Pressure Drop and Flow Instability in Evaporative Micro-Channels

2008 ◽  
Author(s):  
Hee Joon Lee ◽  
Dongyao Liu ◽  
Shi-Chune Yao
Keyword(s):  
Pressure Drop ◽  
Flow Instability ◽  
Experimental Studies ◽  
Bond Number ◽  
Effective Length ◽  
Instability Criterion ◽  
Micro Channel ◽  
Micro Channels ◽  
Wide Range ◽  
Channel Systems

Experiments were conducted on evaporative micro-channel systems of water, containing 48 parallel channels of 353 μm hydraulic diameter. The general correlation of two-phase pressure drop for an initial design purpose of evaporative micro-channel systems reported in [1] has been validated. For the water boiling in micro-channels, flow instability was observed. The instability criterion, proposed by Kandlikar [2], is able to predict the water experimental results. However, further examination of his criterion revealed that it can not predict the results of Brutin and Tadrist’s data of n-pentane. This is because the Bond number of water is 0.01, but 0.33 for n-pentane. As a result, the growing bubble of n-pentane may not cover the whole length of the micro-channel. A general expression of the effective length of squeezed bubbles in micro-channel was established for fluids at a wide range of Bond number. Using this proposed effective length, the Brutin and Tadrist’s experimental instability data can also be predicted satisfactorily.

Dynamic Behavior and Design of Offshore Caissons

1978 ◽  
Vol 18 (05) ◽  
pp. 291-299
Author(s):  
S.T. Hong ◽  
J.C. Brooks
Keyword(s):  
Dynamic Behavior ◽  
Experimental Studies ◽  
Design Procedure ◽  
Operational Experience ◽  
Dynamic Effects ◽  
Free Standing ◽  
Well Production ◽  
Single Well ◽  
Time Required ◽  
Short Time

Abstract Free-standing caissons are used for supporting flare pipes and single-well production platforms. However, caissons tend to be flexible and dynamically sensitive, and the static design practice may not be adequate for this type of practice may not be adequate for this type of structure. To assess motion effect on the integrity of the structural system and to quantify the allowable motion for safe operation on board a caisson platform, analytical and experimental studies of platform, analytical and experimental studies of the dynamic behavior of a caisson structure were conducted and are described here. The analytical simulations agree well statistically with The motion measurements. A caisson design procedure considering dynamic effects was developed Design considerations include ultimate strength failure, fatigue failure, excessive motion, and possible damage during installation. A key feature in an effective caisson design is that the upper part of the caisson should be made as small as possible so that wave loading and the caisson period can be minimized The fatigue design procedure was verified with past caisson operational experience. To illustrate past caisson operational experience. To illustrate the procedure, a flare-pipe support caisson in 185 ft of water was designed and analyzed. Introduction Free-standing caissons are used for supporting flare pipes or single-well production platforms. The attractiveness of a caisson structure lies in the potential economy and the short time required for potential economy and the short time required for fabrication and installation. However, a caisson tends to be flexible, and dynamic effects may increase the design requirements from both strength and functional standpoints. To assess the motion effect on the integrity of the structural system and to quantify the allowable motion level for effective operation on board a caisson platform, analytical and experimental studies of the dynamic behavior of a caisson structure were conducted, and a procedure was formulated for designing a caisson considering dynamic effects. Observations from the experimental data and computer simulations of the caisson behavior are described. Verification of the computer simulation and some useful information for developing and using such simulations as well as practical interpretation of the analytical results practical interpretation of the analytical results also are given. Differences between a static design and a dynamic design are illustrated in an example design of a flare-support caisson in 185 ft water. MOTION MEASUREMENT Motion data were taken from a caisson platform offshore Louisiana. General dimensions of the caisson are shown in Fig. 1. SPEJ P. 291

A Photographic Study of Boiling in the Absence of Gravity

1959 ◽  
Vol 81 (3) ◽  
pp. 230-236 ◽  
Author(s):  
R. Siegel ◽  
C. Usiskin
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Boiling Heat Transfer ◽  
High Speed ◽  
Free Fall ◽  
Nucleate Boiling ◽  
Zero Gravity ◽  
Experimental Equipment ◽  
Boiling Process ◽  
Qualitative Effect

A photographic study was made to determine the qualitative effect of zero gravity on the mechanism of boiling heat transfer. The experimental equipment included a container for boiling water and a high-speed motion-picture camera. To eliminate the influence of gravity, these were mounted on a platform which was allowed to fall freely approximately 8 ft. During the free fall, photographs were taken of boiling from various surface configurations such as electrically heated horizontal and vertical ribbons. The heat flux was varied to produce conditions from moderate nucleate boiling to burnout. The results indicate that gravity plays a considerable role in the boiling process, especially in connection with the motion of vapor within the liquid.

Free Fall Water Entry of a Two-Dimensional Asymmetric Wedge in Oblique Slamming: A Numerical Study

2020 ◽  
Author(s):  
Saeed Hosseinzadeh ◽  
Mohammad Izadi ◽  
Kristjan Tabri
Keyword(s):  
Numerical Study ◽  
Experimental Studies ◽  
Free Fall ◽  
Water Entry ◽  
Vertical Acceleration ◽  
Two Dimensional ◽  
Pile Up ◽  
Real Phenomenon ◽  
Precise Simulation ◽  
Good Agreement

Abstract This paper examines the hydrodynamic problem of a two-dimensional symmetric and asymmetric wedge water entry through freefall motion. The gravity effect on the flow is considered and because of precise simulation close to the real phenomenon, the oblique slamming is analyzed. The defined problem is numerically studied using SIMPLE and HRIC schemes and by implementing an overset mesh approach. In order to evaluate the accuracy of the numerical model, the present results are compared and validated with previous experimental studies and showed good agreement. The results are presented and compared for each symmetry and asymmetry in different deadrise angles, drop heights and heel angles. Based on a comparison of the measured vertical acceleration of the experimental wedge data, it is determined that the proposed numerical method has relatively good accuracy in predicting the slamming phenomenon and wedge response. The influence of viscous regime on water entry simulations is investigated, in according to results, effect of viscosity is negligible. Results show that the heel angle dramatically affects the wedge dynamics, pile-up evolution, and pressure distribution. These results suggest evidence for a complex interaction between geometric parameters on the water entry of rigid wedges, which could finally develop our understanding of planing vessels operating in real sea conditions.

FEASIBILITY ANALYSIS OF LIQUID PROPELLANT SETTLING IN THE TANKS OF A SPACE PROPULSION SYSTEM AFTER FLYING IN ZERO GRAVITY USING A SEPARATING TURN MANUEVER OF THE ORBITAL UNIT

2021 ◽  
pp. 78-87
Author(s):  
Nikolay N. TUPITSIN
Keyword(s):  
Attitude Control ◽  
Feasibility Studies ◽  
Propulsion System ◽  
Zero Gravity ◽  
Liquid Propellant ◽  
Propulsion Systems ◽  
Rocket Propulsion ◽  
Liquid Rocket Propulsion ◽  
Liquid Rocket ◽  
Main Engine

The paper presents results of preliminary design feasibility studies of using inertial settling of liquid propellant in tanks of space liquid rocket propulsion systems and separating from the propellant the ullage gases formed in zero gravity by means of centrifugal forces generated when the orbital unit performs the programmed turn maneuver proposed by the author. It shows that performing propellant settling and ullage gas separation by means of the separating turn maneuver makes it possible to significantly reduce propellant consumption in propulsion systems for attitude control and ullage engines. Key words: space liquid rocket propulsion system, main engine, separation of ullage gases from liquid propellant, separating turn maneuver of the orbital unit.

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