A New Intermittent Aspirated Probe for the Measurement of Stagnation Quantities in High Temperature Gases

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Michela Massini ◽  
Robert J. Miller ◽  
Howard P. Hodson
Keyword(s):  
High Temperature ◽  
Mass Flow ◽  
Flow Rate ◽  
Stagnation Pressure ◽  
Stagnation Temperature ◽  
Measuring Device ◽  
Second Mode ◽  
Total Temperature ◽  
Flow Through ◽  
Temperature And Pressure

This paper presents the design, manufacture, and testing of a new probe for the measurement of temperature and pressure in engine environments. The probe consists of a choked nozzle located in the flow and a system downstream including a cooler, a flow measuring device, and a valve. It operates in two modes: In the first mode the valve is open, the probe is aspirated, and the nozzle is choked. The mass flow through the probe is measured using instrumentation placed downstream of the cooler, so that it does not have contact with the hot flow. In the second mode, the valve is closed, and the stagnation pressure is measured using the same instrumentation downstream the cooler. The total temperature is computed as a derived variable from the measurements of stagnation pressure and mass flow rate. There are a number of advantages of the probe over existing methods of temperature measurement. The measurement inaccuracy due to conduction and radiation errors and calibration drift found in thermocouples is significantly reduced; it can measure both stagnation temperature and pressure, halving the instrumentation costs; it has no wiring or transducer in the sensor head; the system can self-calibrate while located within an engine. This paper describes the design of a probe for use in engine environments. The probe prototype is tested up to 900 K and is shown to have an accuracy of ±6 K.

A New Intermittent Aspirated Probe for the Measurement of Stagnation Quantities in High Temperature Gases

2008 ◽  
Author(s):  
Michela Massini ◽  
Robert J. Miller ◽  
Howard P. Hodson
Keyword(s):  
High Temperature ◽  
Mass Flow ◽  
Flow Rate ◽  
Stagnation Pressure ◽  
Stagnation Temperature ◽  
Measuring Device ◽  
Second Mode ◽  
Total Temperature ◽  
Flow Through ◽  
Temperature And Pressure

This paper presents the design, manufacture and testing of a new probe for the measurement of temperature and pressure in engine environments. The probe consists of a choked nozzle located in the flow and a system downstream including a cooler, a flow measuring device and a valve. It operates in two modes: in the first mode the valve is open, the probe is aspirated and the nozzle is choked. The mass flow through the probe is measured using instrumentation placed downstream of the cooler, so that it does not have contact with the hot flow. In the second mode the valve is closed and the stagnation pressure measured using the same instrumentation downstream the cooler. The total temperature is computed as a derived variable from the measurements of stagnation pressure and mass flow rate. There are a number of advantages of the probe over existing methods of temperature measurement. The measurement inaccuracy due to conduction and radiation errors and calibration drift found in thermocouples is significantly reduced; it can measure both stagnation temperature and pressure, halving the instrumentation costs; it has no wiring or transducer in the sensor head; the system can self-calibrate while located within an engine. The paper describes the design of a probe for use in engine environments. The probe prototype is tested up to 900K and shown to have an accuracy of ±6K.

A Novel Technique for Measuring Stagnation Quantities and Gas Composition in High Temperature Flows

2010 ◽  
Author(s):  
Michela Massini ◽  
Robert J. Miller ◽  
Howard P. Hodson ◽  
Nick Collings
Keyword(s):  
High Temperature ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Turbines ◽  
Stagnation Pressure ◽  
Temperature Measurements ◽  
Stagnation Temperature ◽  
Gas Composition ◽  
Reference Measurements

A new probe has been developed to measure the time averaged stagnation temperature, stagnation pressure and gas composition. This probe can be used in the high temperature regions of gas turbines, including downstream of the combustor and in the first stages of the high pressure turbines, as well as in other environments. The principal benefits of the new probe are that it overcomes the limitations of the standard methods that are used to measure temperature in high temperature environments and that it replaces three separate probes, for the three quantities mentioned above, with one single probe. A novel method of measuring temperature is used, which improves upon the accuracy of thermocouples and increases the temperature operating range. The probe consists of a choked nozzle placed in the hot flow at the point of interest. The working principle is based on the theory that for a choked nozzle, there is a fixed relationship between the stagnation quantities, the gas characteristics and the mass flow rate through the nozzle. The probe has an aspirated phase, where the gas composition and the mass flow rate are measured and a stagnated phase, where the stagnation pressure is measured. The stagnation temperature is determined from the above quantities. The operating principle has been proven valid through laboratory and rig tests. The probe has been successfully tested in a Rolls-Royce Viper engine up to 1000K and 2 bar and in a combustor rig up to 1800K and 4 bars. Measurements of stagnation temperature, stagnation pressure and gas compositions for these tests are presented in the paper and are compared with reference measurements. The accuracy of stagnation pressure and gas composition measurements is equal to the accuracy achievable with techniques that are commonly used in gas turbines. The estimated achievable accuracy of the aspirated probe in terms of temperature measurements is ±0.6%, i.e. ±10K at 1800K, which improves upon the accuracy of temperature measurements performed with standard thermocouples at the same temperatures, the uncertainty of which could be as high as ±2%.

Superflow of helium II through compressed powder

1953 ◽  
Vol 218 (1132) ◽  
pp. 18-28 ◽  
Keyword(s):  
Flow Rate ◽  
Thermal Gradient ◽  
Heat Current ◽  
Satisfactory Explanation ◽  
Intermediate Point ◽  
Helium Ii ◽  
Flow Phenomena ◽  
Similar Character ◽  
Flow Through ◽  
Temperature And Pressure

The flow of liquid helium II through a tube packed with rouge powder has been investigated under gradients of temperature and pressure. The flow rate, the heat current and the pressures at the ends of the tube as well as at an intermediate point have been determined at various temperatures. In flow under a thermal gradient a similar character to that earlier established for flow through narrow slits has been observed. Up to a certain critical velocity which depends on temperature, the flow is free of friction, while at higher velocities, dissipation sets in. The flow under gravity differed completely in its behaviour from the observations with the slit, since dissipation occurred at all velocities. This inconsistency in the flow phenomena has been discussed but no satisfactory explanation can be offered.

scholarly journals Numerical Investigation of the Hub-Seal Mass Flow Rate Effect on the Axial Turbine Stage Efficiency

2019 ◽  
Vol 213 ◽  
pp. 02080
Author(s):  
Petr Straka
Keyword(s):  
Numerical Simulation ◽  
Mass Flow Rate ◽  
Compressible Flow ◽  
Mass Flow ◽  
Flow Rate ◽  
Turbine Stage ◽  
Axial Turbine ◽  
Flow Through ◽  
Stage Efficiency ◽  
Flow Rate Effect

The contribution deals with numerical simulation of compressible flow through the axial turbine stage equipped with the hub-seal. The current flowing from the hub-seal has a major impact on the secondary flow in the hub-region of the blade span. The aim of this work is to found a dependency of the efficiency-drop on the hub-seal mass flow rate. Numerical simulation has been made for configuration of experimental axial single-stage reaction turbine.

Analysis on slot-type casing treatment injection flow in an axial transonic compressor

2016 ◽  
Vol 230 (8) ◽  
pp. 792-804 ◽  
Author(s):  
Mingmin Zhu ◽  
Xiaoqing Qiang ◽  
Wensheng Yu ◽  
Jinfang Teng
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Axial Direction ◽  
Stall Margin ◽  
Rotating Speed ◽  
Casing Treatment ◽  
Transonic Compressor ◽  
Injection Flow ◽  
Flow Through

The purpose of this work is to understand the properties of the injection flow through slots opening surfaces with steady and unsteady simulations. The feasibility of evaluating slot effectiveness by steady results is demonstrated. Transient features of injection flow are detailed investigated. Numerical investigations are carried out in a 1.5 axial transonic compressor stage at a specified rotating speed with seven kinds of slot-type casing treatments. Comparisons between steady/unsteady results show that differences of overall performance and injection mass flow rate are dependent on simulation methods, rather than slot configurations. Thus, correlation analysis by steady results of seven slot configurations is considered valid and reveals strong linear correlation between injection mass flow and stall margin improvements/efficiency drops. Therefore, it is practical to evaluate the effectiveness of a specific slot configuration in this compressor with steady results by calculating injection mass flow rate. Afterwards, unsteady simulations are performed with a specific configuration of arc-curve skewed slots. It is clarified that the dividing locations between suction/injection regions moves along the axial direction based on the relative rotor/slots location. Exchanging flow through slots opening surfaces displays periodic variations over time. The variation cycle for one single slot equals blade passing period T. For summation of mass flow through all slots, the cycle equals to T divided by slots number in one passage. The net flow rate through all opening surfaces is always less than zero during a blading passing period, i.e. injection mass flow rate is larger than suction flow all the time.

Stagnation pressure effect on the supersonic minimum length nozzle design

2019 ◽  
Vol 123 (1265) ◽  
pp. 1013-1031
Author(s):  
T. Zebbiche
Keyword(s):  
High Temperature ◽  
State Equation ◽  
Calculation Model ◽  
Stagnation Pressure ◽  
Molecular Vibration ◽  
Minimum Length ◽  
Stagnation Temperature ◽  
Nozzle Design ◽  
Algebraic Equations ◽  
Axisymmetric Minimum Length Nozzle

ABSTRACTThe aim of this work is to develop a calculation model based on the method of characteristics making it possible to study the effect of the stagnation pressure of the combustion chamber on the 2D and axisymmetric minimum length nozzle design giving a uniform and parallel flow at the exit section. The model is based on the use of the real gas approach. The co-volume and the intermolecular interaction effect are taken into account by the use of the Berthelot state equation. The effect of molecular vibration is considered in our model to evaluate the behaviour of gas at a high temperature. In this case, the stagnation pressure and the stagnation temperature are important parameters in our model. The resolution of the algebraic equations is done by the finite difference corrector predictor algorithm. The validation of the results is controlled by the convergence of the critical section ratios calculated numerically as obtained by the theory. The mass and the thrust are evaluated to improve the efficiency of the nozzle. The comparison is made with the high temperature and perfect gas models. The application is made for air.

Continuous-flow high temperature and pressure water sterilizer

2015 ◽  
Vol 10 (1) ◽  
pp. 19-24
Author(s):  
Adrian Ponce
Keyword(s):  
High Temperature ◽  
Flow Rate ◽  
Continuous Flow ◽  
Low Cost ◽  
Water Flow Rate ◽  
Geobacillus Stearothermophilus ◽  
High Temperature And Pressure ◽  
Point Of Use ◽  
Pressure Water ◽  
Temperature And Pressure

Water sterilization at sterility assurance levels exceeding 10−6 has been achieved with a novel high temperature and pressure sterilization system (HAPSS) capable of continuous-flow sterilization. The tested sterilizer produces >2,000 L/day and does not require filters, moving parts, or regular maintenance and can operate for multiple years with only water and standard voltage/amperage electricity. Sterility assurance levels were determined using Geobacillus stearothermophilus spores with inactivation experiments as a function of temperature and flow rate (i.e., duration/dosage at given temperature). Sterility of 1.0 × 104 CFU/mL G. stearothermophilus spore suspensions was achieved at the highest water flow rate of 1.4 L/min at 140 and 130 °C. The low cost and maintenance-free operation of HAPSS is envisioned to impact water sterilization needs of developing nations, hospitals, and commercial point of use applications.

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