Performance study of an inlet in supersonic flow

2012 ◽  
Vol 227 (1) ◽  
pp. 159-174 ◽  
Author(s):  
Mohammad R Soltani ◽  
Mohammad Farahani
Keyword(s):  
Mach Number ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Free Stream ◽  
Characteristic Curve ◽  
Pressure Recovery ◽  
Internal Boundary ◽  
Performance Study ◽  
Free Stream Mach Number

The performance characteristics of an axisymmetric inlet at its design and off-design operational conditions are experimentally investigated. The model is tested for wide ranges of free stream Mach numbers, M∞ = 1.5–2.5, and mass flow rates. For each test, the pressure recovery, the mass flow passing through the inlet and the pressure distribution over the spike and the cowl are measured. In addition, the shock wave formed in front of the inlet is visualized. The characteristic curve of the inlet is then obtained for each free stream Mach number. As the Mach number is increased, the pressure recovery is reduced, but the maximum value of the mass flow rate grows up. Variations of the mass flow affect the surface pressure over both the front portion of the cowl and the entire surface of the spike. Further, it has changed both pressure and Mach number at the end of the diffuser, which would consequently affect the performance of the propulsion system. In addition, contrary to the internal boundary layer, the external one far from the cowl lip has been found to be almost independent of the inlet mass flow rate for a constant free stream Mach number.

scholarly journals Comparison of Swing and Tilting Check Valves Flowing Compressible Fluids

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 758
Author(s):  
Zhi-xin Gao ◽  
Ping Liu ◽  
Yang Yue ◽  
Jun-ye Li ◽  
Hui Wu
Keyword(s):  
Mach Number ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Check Valve ◽  
Small Mass ◽  
Working Fluid ◽  
Valve Disc ◽  
Valve Opening ◽  
The Difference

Although check valves have attracted a lot of attention, work has rarely been completed done when there is a compressible working fluid. In this paper, the swing check valve and the tilting check valve flowing high-temperature compressible water vapor are compared. The maximum Mach number under small valve openings, the dynamic opening time, and the hydrodynamic moment acting on the valve disc are chosen to evaluate the difference between the two types of check valves. Results show that the maximum Mach number increases with the decrease in the valve opening and the increase in the mass flow rate, and the Mach number and the pressure difference in the tilting check valve are higher. In the swing check valve, the hydrodynamic moment is higher and the valve opening time is shorter. Furthermore, the valve disc is more stable for the swing check valve, and there is a periodical oscillation of the valve disc in the tilting check valve under a small mass flow rate.

Experimental Investigation of Flow Instability in a Supersonic Inlet

2010 ◽  
Author(s):  
Mohammad Reza Soltani ◽  
Mohammad Farahani
Keyword(s):  
Mach Number ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Flow Instability ◽  
Wind Tunnel Test ◽  
External Flow ◽  
Pressure Data ◽  
Supersonic Inlet ◽  
Shock Oscillation

An extensive wind tunnel test series were conducted on an axisymmetric supersonic inlet. The model was tested at Mach numbers from 1.8 to 2.2 and at different values of mass flow rate. Shadowgraph flow visualization was used to capture the external shock structure in front of the inlet. The goal of this study is to find out the general characteristics of the inlet buzz. Frequencies of the buzz have been achieved from the analysis of the pressure data as well as the shadowgraph pictures. The amplitude of the shock waves motion has been measured from the visualization pictures too. In the some large value of mass flow rate, the frequency of shock oscillation increased versus Mach number. Also in each Mach number due to the mass flow rate decrement, the buzz frequency decreases and its amplitude increases conversely. Also buzz instability affects the external flow by the same frequency of the internal one.

Unstart phenomena induced by mass addition and heat release in a model scramjet

2016 ◽  
Vol 797 ◽  
pp. 604-629 ◽  
Author(s):  
S. Im ◽  
D. Baccarella ◽  
B. McGann ◽  
Q. Liu ◽  
L. Wermer ◽  
...  
Keyword(s):  
Heat Release ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Speed ◽  
Free Stream ◽  
Mass Loading ◽  
High Enthalpy ◽  
Hypersonic Wind Tunnel ◽  
Flow Features

The unstart phenomena in a model scramjet with a free stream Mach number of 4.5 were investigated at an arc-heated hypersonic wind tunnel. High-speed schlieren imaging and high resonance frequency pressure measurements were used to capture the flow features during the unstart process. Three unstart conditions were tested: (i) a low-enthalpy free stream with mass loading, (ii) a high-enthalpy free stream with mass loading and (iii) a high-enthalpy free stream with mass loading and heat release. It was revealed that the unstart threshold and the time from the onset to the completion of unstart depended strongly on the mass loading rate and the heat exchange. The negative heat addition (cooling) significantly increased the threshold of mass flow rate triggering unstart. The decrement of the mass flow rate threshold for unstart was observed in the presence of heat release by combustion. The observed transient and quasi-steady behaviours of the unstart shockwave system and the jet motion were similar in all of the test conditions. On the other hand, at the lip of inlet model, the unstart shockwave under the cold free stream condition exhibited a relatively steady behaviour while severe oscillatory flow motions of the jet and the unstart shockwave were observed in the combustion-driven unstart process. The different unstarted flow behaviours between the three flow conditions were explained using a simplified one-dimensional flow choking analysis and use of the Korkegi criterion.

scholarly journals Drying of mint leaves in forced convection solar dryer

2019 ◽  
Vol 23 (6 Part B) ◽  
pp. 3941-3949
Author(s):  
Munusamy Suresh ◽  
Ponnusamy Palanisamy ◽  
Kumar Senthil
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Work Performance ◽  
Drying Process ◽  
Performance Study ◽  
Absorber Plate ◽  
Forced Air ◽  
Drying Efficiency ◽  
Iron Tube

In this present work, performance study on drying mint leaves under the metrological conditions. Intensity of radiation falls on the absorber plate which transfers heat to forced air-flow inside the galvanized iron tube. Drying experiment carried out with 1 kg of mint leaves taken for drying process under the different mass-flow rate of 0.75 m/s and 1.25 m/s in serpentine flow of air. Performance of the collector and drying efficiency were 30.33% and 1.63% in first day at 0.75 m/s mass-flow rate and in the second day collector, the drying efficiency were 29.41% and 1.89% at the mass-flow rate of 1.25 m/s. The mass-flow rate of air decreased with increasing collector and drying efficiency.

scholarly journals Analysis and Development of Restrictor for Parallel Twin Engine in FSAE Cars

2018 ◽  
Vol 7 (3.6) ◽  
pp. 311 ◽  
Author(s):  
M Vignesh Kumar ◽  
Sivanesan Murugesan
Keyword(s):  
Mach Number ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Software Tool ◽  
Ansys Fluent ◽  
Formula Sae ◽  
Standard Design ◽  
Fluent Software ◽  
Convergence And Divergence

This research aims to the development of intake restrictor of a formula SAE car engine which is of 300cc parallel twin cylinder engine. In this paper we have considered different venturi designs which have different convergence and divergence angles. The main aim is to optimize the pressure and velocity of air which tends to offer better combustion reflects in performance. The parameters which are to be considered for design as well as analysis are mach number, intake velocity, mass flow rate, etc.., To perform this research we have chosen the Ansys fluent software tool and the analytical calculations were made for standard design. It is observed that the continuous variations in converging and diverging angles offers better results in both pressure and velocity characteristics of air entering for combustion. 

Active Stabilization of Centrifugal Compressor Using Adjustable Geometry Impeller

2001 ◽  
Author(s):  
K. M. Saad Eldin
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Speed ◽  
Characteristic Curve ◽  
Pressure Ratio ◽  
Rotating Stall ◽  
Maximum Efficiency ◽  
Impeller Blade ◽  
Stable Regime

Abstract Recent work has shown that variable impeller geometry of the centrifugal compression system can be actively stabilized against the instability known as surge, thereby realizing a significant gain in system mass flow rate. In this context, the paper presents an experimental study about the influence of the impeller blade configuration on the extension of the stabilized characteristic margin beyond the natural surge line and enlarge the usable compressor operating region. This method is estimated from the two major control methods which: surge avoidance control and surge suppression control. The impeller of tandem type with zero overlap is found to be a good sample to satisfy the above concept. The impeller is working as full bladed at stable regime, but it could be transferred into tandem bladed when the mass flow rate decreases below a certain minimum value, just before rotating stall occurs. The operating point moves downwards to another characteristic curve belonging to the new configuration, which has a surge margin less than the original one by 56 percent, at high speed. Herein the effect of tandem shift angle on extending the stabilized range is studied experimentally and a control criterion is suggested. The pressure ratio at the new characteristic curve is decreased by about 3 percent and maximum efficiency is decreased also by about 28 percent.

Design and aerodynamic performance analysis of a variable geometry axisymmetric inlet for TBCC

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yunfei Wang ◽  
Huacheng Yuan ◽  
Jinsheng Zhang ◽  
Zhenggui Zhou
Keyword(s):  
Mach Number ◽  
Performance Analysis ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Design Method ◽  
Aerodynamic Performance ◽  
Combined Cycle ◽  
Variable Geometry

Abstract Design and aerodynamic performance analysis of a variable geometry axisymmetric inlet was carried out for tandem scheme turbine-based combined cycle (TBCC) propulsion system. The operation Mach number of the inlet was between 0 and 4. The design point was chosen as Mach number 4.0 in this paper. The determination of external and internal compression and the design method of annular to circle diffuser were illustrated. The inlet was unstart under Ma 3.0 without adjustment. Then, a variable scheme was designed to ensure self-start of the inlet and match the requirement of mass flow rate during the whole flight envelope. And four supports were used to fix the spike. According to the 3D numerical simulations, the total pressure recovery was 0.52 at Ma 4.0 at critical condition and the mass flow rate was consistent with the requirement at different flight Mach number.

Effects of Ice Formation on the Flowfield of an Aircraft Engine Inlet

2008 ◽  
Author(s):  
Ray R. Taghavi ◽  
Wonjin Jin
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Total Pressure ◽  
Free Stream ◽  
Flow Region ◽  
Aircraft Engine ◽  
Ice Formation ◽  
Ice Accretion ◽  
Mach Numbers

The effects of typical rime and glaze ice on the performance of the M2129 S-duct inlet are computationally investigated using the steady-state RANS solution. The glaze ice accretion produces a substantial degradation of the inlet performance due to its obstructive shape to the in-flow, while the effect of the rime ice is not significant. Compared to the clean inlet, the secondary flow region at the engine face of the duct inlet is increased by 600 percent for the glaze iced inlet. Total pressure recoveries at the engine face for the rime and glaze ice case are 98.8 and 95.8 percent, respectively. Also, the glaze ice causes 26 percent reduction in the mass flow rate at the engine face. In addition, the adverse effects on the performance of the inlet are enhanced by an increase in freestream Mach numbers due to the stronger and more extensive shock formations in the inlet flow. With increasing free stream Mach numbers from M∞ = 0.13 to 0.85, total pressure recovery decreases from 0.985 to 0.62 with the glaze ice accretion. And the level of the mass flow rate with the glaze ice accretion is 76 percent of that in ice-free condition at M∞ = 0.13; however, it decreases to 68 percent at M∞ = 0.475.

An experimental study of compressible combining flow at 45° T-junctions

2014 ◽  
Vol 229 (9) ◽  
pp. 1600-1610 ◽  
Author(s):  
Wenhui Wang ◽  
Zhenhua Lu ◽  
Kangyao Deng ◽  
Shuan Qu
Keyword(s):  
Experimental Study ◽  
Mach Number ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Loss ◽  
Measurement Data ◽  
Junction Flow ◽  
Wide Range ◽  
Loss Coefficients

Junction flow loss is one of the sources of flow losses in many engineering pipe systems. An experimental study was carried out in order to investigate the combining steady pressure loss coefficients at 45° T-junctions with three area ratios between lateral branch and main duct. Extensive measurement data were obtained at a wide range of Mach number (0.1–0.6) and mass flow rate ratios using air as the tested fluid. Comparative analysis of the results includes the pressure difference in the two flow paths of the junction, the effect of Mach number in common branch due to gas compressibility, as well as the loss coefficients with various geometry condition. The following conclusion is drawn: the total pressure loss coefficient ( K) was mainly dependent on the Mach number ( M3), mass flow rate ratio ( q), and area ratio ( a), while almost independent on Reynolds number. The results provide reference for the research of junction flow and can be valuable in the correction of the boundary condition in one-dimensional simulation models.

Numerical Study of Supersonic Film Cooling in Diverging Section of Nuclear Rocket Laval Nozzle

2018 ◽  
Author(s):  
Xiaokai Sun ◽  
Ping Ye ◽  
Peixue Jiang ◽  
Wei Peng ◽  
Jie Wang
Keyword(s):  
Mach Number ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Film Cooling ◽  
Laval Nozzle ◽  
Numerical Study ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Nuclear Rocket

Nuclear rockets with specific impulse have obvious advantages by greatly reducing the mass of the propellant and potentially decreasing the cost of launching material from the earth’s surface. Nuclear thermal rockets use hydrogen propellant with coolant exit temperature of near 3000 K, which is very high, so the cooling of airframe surfaces in the vicinity of the exhaust is needed, of which film cooling is an effective method. Most of previous studies mainly focus on the film cooling effectiveness using two dimensional backward-facing step model, however, the nuclear rocket exhaust using the converging-diverging Laval nozzle, so the film cooling would be different. The present study numerically investigated the influence of coolant Mach number, coolant inlet height on supersonic film cooling in the diverging section of Laval nozzle, while keeping the coolant mass flow rate constant, with the results showing that: increasing the coolant inlet Mach number and the coolant inlet height can increase the film cooling effectiveness; for the same coolant mass flow rate, reducing the coolant inlet height and increasing the inlet Mach number improves film cooling effectiveness.

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