Fang Lide

Design and simulation of fuzzy control system for water temperature of Heat exchanger

Generally, It is difficult to build an exact mathematical model for extremely complexity of the heat transfer process of Heat exchanger and it is hard to perform control with traditional techniques. So this paper proposed a kind of fuzzy controller with intelligence integral, and uses MATLAB as a visual modeling tool to combine the theoretical study with the realization in engineering, simulation research based on SIMULIK, The simulation result show that the controller has good control quality for the system of the heat transfer.

Venturi Wet Gas measurement based on homogenous and chisholm model

When Venturi meters are used in wet gas the measured differential pressure is higher than it would be were the gas phases flowing alone. This phenomenon is called over reading, This paper proposed a new Venturi wet gas correlation based on homogenous and separated assumption, and its validity is verified through experiment. a new test program has been implemented in Tianjin Universitys Low Pressure Wet Gas Loop. Three 50mm Venturi meters, with β values of 0.4048, 0.55 and 0.70 have been tested at the working operation pressure of 0.15, 0.20 and 0.25 MPa, and the gas densiometric Froude number from 0.6 to 2.5, the modified Lockhart-Maretinelli parameter from 0.0022 to 0.3, and the ratio of the gas liquid mass flow rate from 0.5 to 0.99. Finally, the performance of the new proposed correlations is compared with the old eight correlations.

Analysis of dynamic model of heating system after step change of water supply temperature

In China, the heating measurement system employed a ball valve to control the flow rate on the pipe inlet of the house. Unsurely, the valve remain turn on when the inhabitant at home and remain cut off when the inhabitant go to work, which can make a step change to water supply temperature. In this paper, the characteristic of the temperature distribution curve of radiator was analyzed in transient, the parallel moving presumption of the temperature distribution curve was proposed, according to the presumption, the functional relation between heat dissipating capacity of radiator and the time in transient was put forward, the rationality of the functional relation was proved by experiments.

Temperature and flow rate compensation for air quality auto-monitoring system based on multi-sensor data fusion

Nowadays, air quality has being worse more and more, air pollution members of automatic monitoring has gained more attention . sulfur dioxide is One of the main pollutants in air, it is an important indicator of atmospheric pollution levels. this paper studies the sample gas temperature and flow rate on impact of sulfur dioxide air quality monitoring system, two sulfur dioxide air quality monitoring system were tested under three standard gas densities, with the changes in the sample gas temperature and the flow rate, the results show that the sample gas temperature and flow rate have significant effect for sulfur dioxide air quality monitoring system, if uncorectted, the relative error would exceed ±8%. finally, a correlation is offered.it makes the relative error reduced form ±8% to ±2%.

Dynamic Error of Heat Measurement in Transient

According to EN1434 (European Standard) and OIML R-75(International Organization of Legal Metrology), there are two methods in heat measurement, and they are all steady-state methods of test, using them in transient, obvious error will be produced, so some accurately measuring functions should be seeking. In a previous published paper of the author, a transient function relationship of heat quantity and time is deduced, and the validity of this function is proved through experimentation, also it is simplified reasonably, so it can be used in variable flow rate heating system. In this study, a comparison with steady-state method and dynamic method is presented, the errors exist in the steady state method are analyzed. A conclusion is improved that the steady-state methods used in variable flow heating system will result in appreciable errors, the errors only exist in transient, when system reach steady state, the errors disappear, moreover, the transient time is long in heating system, it is at least 30 minutes, so it is necessary to take some measures to correct them, however, study showed that the error can be ignored when the flow rate step change is less than 5kg/h.

A New Intelligence Dynamic Heat Meter

According to EN1434 (European Standard) and OIML R-75(International Organization of Legal Metrology), there are two methods in heat measurement, and they are all steady-state methods of test. The performances of these two methods are analyzed. A conclusion is improved that the two methods used in variable flow heating system results in appreciable errors. So some accurately measuring models should be seeking. In another accepted paper of the author, a transient function relationship of heat quantity and time is deduced, and the validity of this function is proved through experimentation, also it is simplified reasonably, so it can be used in variable flow rate heating system. According to the simplified formula, a dynamic intelligence heat meter is designed, and the hardware and software of intelligent dynamic heat meter by using the MSP430 single chip microcomputer is discussed. The character of this heat meter can be seen as follow. The supply water temperature, return water temperature and the variation of the flux of heating system are detected in real time. When step change happened, dynamic heat meter can measure heat dissipating capacity accurately, at the same time, the steady heat dissipating capacity can be measured accurately too. The meter used in heating system can adjust room temperature intelligently according to the hosts request

Wet gas measurement characteristics of a vortex flow meter

Wet gas is a particular form of gas liquid two phase flow, normally; it can not be seen as single phase flow. when a single phase flow meter used in wet gas, appreciable errors will be produced, even, a measurement dispute would be generated, so it is extremely urgent to develop a online wet gas flow meter to measurement the gas volume fraction accurately. This paper present a review of Vortex wet gas measurement, the theory of Vortex wet gas measurement also be introduced, moreover, the performance of an vortex flowmeter in wet gas flow was investigated under the condition of different liquid volume fraction, pressure and gas mass fraction, finally, some advice were offered.

Slip property of oil-water two phase flow in horizontal pipe

Normall, it is very difficult to measurement oil volume fraction under low oil volume fraction in multi phase flow measurement, in this study, Slip property of oil-water two phase flow in horizontal pipe under low oil volume fraction was investigated though a Coriolis Mass Flowmeter, the difference of water cut and water hold up was analyzed with experiment under the same liquid flow rate, and the same water cut with different oil water speed, the results will offer valuable reference to oil content measurement.

Effect of step change of water supply temperature on heating measurement system

In heating measuring system, the water supply temperature of the heat source is requested invariable, it adopts the mode of changeable flow adjustment to change the capacity of heat supply, but in the actual operation it relates to the maintenance of the system and the sewage discharge, especially to the heating system of the boiler room. Furthermore, the heating measurement system unsurely employed a ball valve to control the flow rate on the pipe inlet of the house, the valve remain turn on when the inhabitant at home and remain cut off when the inhabitant go to work. All these reasons result in the temperature of water supply system has a sudden variety. In this paper, the characteristic of the temperature distribution curve of radiator was analyzed in transient, according to the the parallel moving presumption, the functional relation between heat dissipating capacity of radiator and the time in transient was put forward, finally, the measurement error of steady-state formula was compared under different water supply temperature and different temperature step change. It provides a valuable reference for the study of dynamic characteristics of variable flow heating system.

A measure for the finite decentralized assignability of eigenvalues of generalized decentralized system

This article give the definition of assignability measue of generalized decentralized control system and the related theorem and the proof as well, which is a natural generalization of conclusion. This measure quantifies how close a mode is to being a finite decentralized fixed mode.If a mode is close to being a FDFM, large controller gains are required to shift it .This result is useful for the analysis of systems with small modeling errors and regularly perturbed systems