Metrological greenhouse gas emission assessment of the transport sector in Türkiye: Towards instrumentation, uncertainty and trends

For measuring the amount of flow of a fluid which goes through a conduit, there are several methods which can be used for this purpose like electromagnetic, thermal, and light methods. One of the useful methods and cost efficient one is using thermal technique to measure the flow. This paper presents a new device for measuring the flow of a fluid. This sensor can measure the amount of mass of the flow in variety velocities which a fluid can has. In this paper a 2-D thermal mass flow meter sensor has been introduced. The proposed sensor consists of two elements that can measure 0-45 m/s in accuracy of 0.01. The first part is heater and the second part is temperature sensor. Keywords Mass flow meter, Temperature sensor, Incompressible fluid dynamics, Heat transfer, COMSOL Multiphysics 1 INTRODUCTION There are two types of thermal mass flow meters in industry. Industrial thermal mass flow meters, also known as thermal dispersion comprise a family of instruments for measurement of total mass flow rate of a fluid, primarily gases, flowing through closed conduits. A second type is the capillary-tube type of thermal mass flow meter; capillary types are primarily used for smaller flows of clean gases or liquids in tubes. This type is most widely used for thermal mass flow meters in industry. Nevertheless, the capillary type is not the subject of this discussion but both types measure fluid mass flow rate by means of the heat convected from a heated surface to the flowing fluid. In the case of the thermal dispersion, or immersible, type of flow meter, the heat is transferred to the boundary layer of the fluid flowing over the heated surface. The fundamental law governing all heat transfer is the first law of thermodynamics [1], commonly referred to as the principle of conservation of energy. However, internal energy,

Potential use of capillary tube thermal mass flow meters to measure residential natural gas consumption

Natural gas compositions variation effect on capillary tube thermal mass flow meter performance

Thermal mass flow meters are widely used in industry for process and plant mass flow metering for a wide range of gas types. The interest of this type of flow meter lies in the fact that the induced pressure drop is negligible; the wide turndown allows measurement of gas consumption as well as leaks. However, the operating conditions of flow meters are sometimes far from the conditions for which the manufacturer specifications are given and the objective of the performed tests is therefore the evaluation of the measurement error which can occur when the use conditions deviate from the calibration conditions. First, tests in “ideal” conditions (no upstream disturbances, ambient conditions of pressure, temperature and humidity) have been performed to check if the flow meters meet their manufacturer’s specifications. Then, some operating conditions have been changed. The investigated parameters were the gas temperature, the gas humidity, the in-line pressure, the orientation of the sensor relative to the flow direction and the distance to upstream disturbances. Tests have been conducted with upstream distances equal to, smaller and higher than the minimum distance required by the manufacturer. The study presented in this paper has been conducted for two insertion type thermal mass flow meters.

Many semiconductor processes require that stable and known flows of gas be delivered to the processing chamber. The thermal mass flow meter (TMFM) is used almost exclusively in the semiconductor industry for the admission of process gases. While TMFM’s have been used in the semiconductor industry for over twenty years, much still remains to be understood about their behavior. The abundance of TMFM manufacturers that make instruments which are supposedly interchangeable complicates the use of TMFM’s because the instruments generally have different designs and performance. While some attempt has been made via written standards to address the specifications of the instruments, these standards do not address all performance issues and cannot eliminate the systematic errors in the original manufacturers calibration of the TMFM’s. Further, the TMFM’s used to measure the process gases are generally calibrated with nitrogen and ‘‘corrected’’ for other gases, but the correction factors are not well understood and are of questionable reliability. It is also important to understand how the TMFM’s perform under conditions that differ from the laboratory conditions where they were calibrated and the measurement errors that are introduced as a result of these different operating conditions. This article presents data on the performance of five low-flow TMFM’s, from different manufacturers, with full scale ranges of 1.5×10−6–3.7×10−6 mol/s (2–5 sccm). The manufacturers’ calibration of the TMFM’s with nitrogen as compared to the National Institute of Standards and Technology (NIST) measured values differed by up to 17%. Three of the five tested TMFM’s were within the manufacturers’ stated tolerance of ±1% of full scale. While some of the instruments’ initial calibration was poor, all of the TMFM’s were stable to within ±1% of full scale over the test interval of nine months. The gas correction factors for five gases (argon, helium, hydrogen, sulfur hexafluoride, and hexafluoroethane) were measured and compared to manufacturers’ recommended values along with the temperature and flow dependence of the gas correction factors. Some of the gas correction factors agreed with the manufacturers’ recommended values to within ±1% while others differed by as much as 13%.

In order to reduce power consumption of thermal mass flow meter and prolong its working life as long as possible, we suppose that a MEMS cantilever beam could be used as switch in thermal mass flow meter. First, we discussed working principle of cantilever beam to confirm the feasibility as switch in circuit. Second, we analyzed its property by using the simulation model. The simulation results show that the bending degree of cantilever beam is not only associated with young's modulus of materials, and also related to cantilever size such as length, thickness and length to width ratio. Therefore, if we can choice suitable material and design reasonable dimension, the MEMS cantilever beam may be used as switch.

To ensure the proper operation of hydroelectric generators, their cooling must be well understood. However, the airflow within such machines is difficult to characterize, and although Computational Fluid Dynamics (CFD) can be a reliable engineering tool, its application to the field of hydroelectric generators is quite recent and has certain limitations which are, in part, due to geometrical and flow complexities, including the coexistence of moving (rotor) and stationary (stator) components. For this reason, experimental measurements are required to validate CFD simulations of such complex flows. Of particular interest is the quantification of the flow within the rotor rim ducts, since it is directly responsible for cooling the poles (one of the most critical components of a hydroelectric generator). Thus, to measure the flow therein, an anemometer was designed. The anemometer had to be accurate, durable, cost-effective, easy to install, and able to withstand the extreme conditions found in hydroelectric generators (temperatures of 45°C, centrifugal forces of 300 g, etc.). In this paper, a thermal mass flow meter and a method for validating its performance, using hot-wire anemometry and a static model of a rotor rim, are described. Preliminary tests demonstrate that the thermal mass flow meter is capable of i) measuring the mass flow rate in the rotor rim ducts with an accuracy of approximately 10%, ii) fitting inside small rectangular ducts (12.2 mm by 51 mm), and iii) resisting forces up to 300 g.

A majority of vacuum processes use the Thermal Mass Flow Meter (TMFM) as metering device for process gas. The purpose of this paper is to establish cross compatibility relationship of the TMFM with different process gases. This paper uses a compressible Computational Fluid Dynamic (CFD) solver to understand the behavior of TMFM with different process gases. The change in the characteristic curve at lower pressures has also been studied. Empirical correlations have been developed so that the change in characteristic curve of TMFM can be predicted accurately for different gases based on their physical properties.

A novel measurement method for identifying the type of gas in a thermal dispersion mass flow meter is presented. The physical background of the gas-identification method is discussed by employing a simple, one-dimensional, mathematical model of a thermal flow sensor. For a practical realization of the gas-identification method, the thermal dispersion mass flow meter has to contain two thermal flow sensors with different constructional or operational parameters. A thermal dispersion mass flow meter containing two thermal flow sensors with circular and square cross-sections was developed and calibrated for five different gases in order to experimentally validate the gas-identification method. If the measurement characteristics for the improper gas are employed, the mass flow readings of the thermal flow sensors will generally differ. The absolute value of the relative difference in the mass flow readings can be used as an objective function for identifying the type of gas from a defined set of gases with known compositions. In addition, the normalized error is proposed as an objective function to consider the dispersion that could be reasonably attributed to the difference in the mass flow readings.

This paper studied the principles of thermal gas mass flow meter. According to the car engine EGR cooler working principle, we found out a kind of heat dissipation gas mass flow meter to measure the mass flow quantity of the gas in the EGR cooler test and analysis system which is a newly applied invention patent. We analyzed various parameters of the gas mass flow meter suitable to the system. Meanwhile, in order to verify reliability of the thermal gas mass flow meter in the system, we adopted CFD method to simulate the EGR cooler by using empirical parameters, and collected several related sensor parameters of the EGR cooler in the condition that the inlet temperature was constantly at 368K while the coolant had 4 kinds of degrees. Combining heat empirical formula, we got the EGR cooler outlet temperature and the overall heat transfer coefficient. After comparing the calculated values of the gas path total EGR cooler outlet temperature and heat transfer coefficients with the experimental values, we found that the outlet temperature values of experiment were smaller than the calculated values by averagely 1.17%, while the average experimental values of the overall heat transfer coefficient were 3.1% larger than the calculated values. Thus, this type of mass flow meter has good stability in the newly applied Chinese patent EGR cooler performance test and analysis system.

Design and application of thermal mass flow meter in space

The Machinery and Engine Technology (MET) Program of the National Research Council of Canada (NRCC) has established a program for the evaluation of sensors to measure gas turbine engine performance accurately. The precise measurement of fuel flow is an essential part of steady-state gas turbine performance assessment. Prompted by an international engine testing and information exchange program, and a mandate to improve all aspects of gas turbine performance evaluation, the MET Laboratory has critically examined two types of fuel flowmeters, Coriolis and turbine. The two flowmeter types are different in that the Coriolis flowmeter measures mass flow directly, while the turbine flowmeter measures volumetric flow, which must be converted to mass flow for conventional performance analysis. The direct measurement of mass flow, using a Coriolis flowmeter, has many advantages in field testing of gas turbines, because it reduces the risk of errors resulting from the conversion process. Turbine flowmeters, on the other hand, have been regarded as an industry standard because they are compact, rugged, reliable, and relatively inexpensive. This paper describes the project objectives, the experimental installation, and the results of the comparison of the Coriolis and turbine type flowmeters in steady-state performance testing. Discussed are variations between the two types of flowmeters due to fuel characteristics, fuel handling equipment, acoustic and vibration interference and installation effects. Also included in this paper are estimations of measurement uncertainties for both types of flowmeters. Results indicate that the agreement between Coriolis and turbine type flowmeters is good over the entire steady-state operating range of a typical gas turbine engine. In some cases the repeatability of the Coriolis flowmeter is better than the manufacturers specification. Even a significant variation in fuel density (10%), and viscosity (300%), did not appear to compromise the ability of the Coriolis flowmeter to match the performance of the turbine flowmeter.

Experimental and simulation studies of the effect of restrictor and distributor on the performance of thermal mass flow meter

Study on the steady-state characteristics of the sensor tube of a thermal mass flow meter

Mortality, Greenhouse Gas Emissions, and Consumer Cost Impacts of Replacing Short Car Trips with Cycling: A Health Impact Assessment Study