Thermal output in a nuclear power plant is verified with calorimetric heat balance on the secondary plant. The calorimetry involves the precise measurement of the feedwater flow rate. However, the correct indication of feedwater flow rate obtained by a pressure-difference measurement across a venturi can be affected by instrument errors, fouling or a poorly developed velocity profile. This can result in an inaccurate mass flow rate and consequently an inaccurate estimate of power. The purpose of this study is to develop verification methods with accuracy better than $0.5\%$ for high precision flow measurement to be used for measuring feedwater flow rate. This chemical tracer method is a testing process that uses tracers which can be applied to quantify losses in electrical output due to the incorrect measurements of feedwater flow rate. And this system has good response to the variation of the flow rate. Accuracy of better than 0.5 percent can be expected for feedwater flow measurement, providing that the system can be stabilized during the test. This methodology is applicable to other flow systems well.
Proceedings of the Korean Nuclear Society Conference
/
1996.05b
/
pp.325-330
/
1996
The existing CHF correlations for internally heated concentric annulus channels are assessed using KAIST CHF database for uniformly heated vertical annuli. Six annulus correlations (Jannsen-Kervinen. Barnett, Levitan-Lantsman, Kumamaru et al., Doerffer et al., and Bobkov et at.) are chosen for assessment based on literature survey and Groeneveld et al.'s CHF table for round tube is also assessed for comparison. Among the above correlations, two are inlet-condition type and others local conditions type. To make the comparison meaningful, the local-condition-type correlations are assessed in two ways: direct substitution method (DSM) and heat balance condition method (HBM). Totally 1174 data are classified into 10 groups based on pressure and mass flux conditions and correlations are assessed to each group separately. Prediction capability of each correlation depends on the data group and none shows the best prediction over the entire group. In overall, the correlations by Doerffer et al. and Jannsen et al. appear to be the best, but Barnett or Levitan-Lantsman correlations also show reasonable prediction for most groups. However, the low-pressure, ]ow flow CHFs are not well predicted by any correlations. The CHF table for round tubes overpredicts the CHF in annuli at fixed local conditions.
This study was carried out find out the appropriate tuning method of PID controller for a package type gas engine cogeneration system in terms of stabilizing the engine coolant temperature and system heat balance. In order to acquire the proper parameters of the controller, a system transfer function was set as a first order plus dead time model and thereafter model parameters were determined by using several tuning methods. And, with determined values of parameters and the system transfer functions, optimal turning method was selected by simulating the process using MATLAB. From the experimental results, it was found that obtained PID gains made the system stable in various operating conditions.
Transactions of the Korean Society of Mechanical Engineers B
/
v.23
no.5
/
pp.670-677
/
1999
An analysis of generation and growth of multicomponent particles has been carried out to predict the size and composition distributions of particles generated in the Modified Chemical Vapor Deposition(MCVD) process. In MCVD process. scale-up of sintering and micro-control of refractive index may need the Information about the size and composition distributions of $SiO_2-GeO_2$ particles that are generated and deposited. The present work solved coupled steady equations (axi-symmetric two dimensions) for mass conservation, momentum balance. energy and species(such as $SiCl_4$, $GeCl_4$, $O_2$, $Cl_2$) conservations describing fluid flow. heat and mass transfer in a tube. Sectional method has been applied to obtain multi-modal distributions of multicomponent aerosols which vary in both radial and axial directions. Chemical reactions of $SiCl_4$ and $GeCl_4$ were included and the effects of variable properties have also been considered.
International Journal of Air-Conditioning and Refrigeration
/
v.8
no.1
/
pp.1-13
/
2000
A numerical study for performance analysis of a crossflow-type forced draft cooling tower has been performed based on the finite volume method with non-orthogonal body fitted, and non-staggered grid system. For solving the coupling problem between water and air, air enthalpy, moisture fraction, water enthalpy, and water mass balance equations are solved with Navier-Stoke's equations simultaneously. For the effect of turbulence, the standard k-$\varepsilon$ turbulent model is implied in this analysis. The predicted result of the present analysis is compared with the experimental data and the commercial software result to validate the present study. The predicted results show good agreement with the experimental data and the commercial software result. To investigate the influence of the cooling tower design parameters such as approach, range and wet bulb temperature, parametric studies are also performed.
Journal of Advanced Marine Engineering and Technology
/
v.8
no.1
/
pp.17-36
/
1984
Since 1973, the competition on the development of fuel saving type internal combustion engines has become severe by the two times oil shock, and new type engines are reported every several months. Whenever these new type engines are developed, new designs are required and they will be offered in the market after performing the endurance test for a long time. But the engine market is faced with a heavy burden of finance, as the developing of a new engine requires tremendous expenses. For this reason, the computer simulation method has been lately developed to cope with it. The computer simulation method can be available to perform the reasonable research works by the theoretical analysis before carrying out practical experiments. With these processes, the developing expenses are cut down and the period of development is curtailed. The object of this study is the development of simulation computer program for the small naturally aspirated four-stroke diesel engine which is intended to product by the original design of our country. The process of simulation is firstly investigated for the ideal engine cycle, and secondly for the real engine cycle. In the ideal engine cycle, each step of the cycle is simulated by the energy balance according to the first law of thermodynamics, and then the engine performance is calculated. In the real cycle imulation program, the injection rate, the preparation rate and the combustion rate of fuel and the heat transfer through the wall of combustion chamber are considered. In this case, the injection rate is supposed as constant through the crank angle interval of injection and the combustion rate is calculated by the Whitehouse-Way equation and the heat transfer is calculated by the Annand's equation. The simulated values are compared with measured values of the YANMAR NS90(C) engine and Mitsubishi 4D30 engine, and the following conclusions are drawn. 1. The heat loss by the exhaust gas is well agree with each other in the lower load, but the measured value is greater than the calculated value in the higher load. The maximum error rate is about 15% in the full load. 2. The calculated quantity of heat transfer to the cooling water is greater than the measured value. The maximum error rate is about 11.8%. 3. The mean effective pressure, the fuel consumption, the power and the torque are well agree with each other. The maximum error is occurred in the fuel consumption, and its error rate is about 7%. From the above remarks, it may be concluded that the prediction of the engine performance is possibly by using the developed program, although the program needs to reform by adding the simulation of intake and exhaust process and assumping more reliable mechanical efficiency, volumetric efficiency, preparation rate and combustion rate.
1. Ounyukki(五運六氣) theory was first developed from observation of astronomical phenomena. Natural phenomena were explained and incorporated into the concepts of Yukki(六氣), and Ohaeng(五行, the concept that all matter in the world are comprised of five fundamental elements), during Chon-guk(戰國) and Han(漢) periods. In that period. Kanji(干支, the method to present time with ten and twelve different kinds of symbol's combinations) was used to record Ounyukki(五運六氣). Theoretical study of Un-gi(運氣, the abbreviation of Ounyukki) was almost completed in Un-gichilpyon(運氣七篇) of Naekyong(內經). Un-gi(運氣) theory was further studied and considered to be very important socially, as well as medically, in Tang(唐), Song(宋), Kum(金), and Won(元) periods. Hagan(河間) published various studies based on Un-gi(運氣) theory in Kum won(金元) periods. 2. Hagan(河間) realized the limitation of a remedy method, of Sanghan(傷寒) theory. Therefore, he made an assumption that the prevalence of diseases in his period are closely related to Hwayol(火熱, a fire and a super-heat; two things out of Yukki(六氣)). His new theory was a result of the study on Kyongjon(經典, bibles of the oriental medicine) and the phenomena of nature. 3. Hagan(河間) used a combination of two basic theories of Pimuripsang(比物立象) and Hanhaesungjeron(亢害承制論) to make understood Hwayol(火熱) theory, Pimuripsang(比物立象) theory explains a method to appreciate the essence of things by comparing Sang(象, an expression of how something appears on the outside) and then making another Sang(象) from the comparison. Hanhaesungjeron(亢害承制論) is a theory to emphasize the importance of a balance of Yukki(六氣). It is that, if one of the elements is exceeded, other thing in the other five elements dominate the exceeded thing to control it for the balance between Yukki(六氣). In addition, he articulated P'yobon(標本. inside and outside of a thing) theory to differentiate the disease symptoms. These theories will help to distinguish real and fake symptoms of diseases, on which Hagan(河間) emphasized its importance. 4. Hagan(河間) published a new theory to explain Ounyukki(五運六氣) theory based on the observation of the nature and the experience from medical practice. And he added Chobyonggi(燥病機, course and rule causing disease in dry conditions) to Pyonggishipkujo(病機十九條, nineteen course and rule causing disease), it strengthened Pyonggi(病機, course and rule causing disease) theories. Moreover. he utilized Un-gi (運氣) theory in a real life situation by applying Un-giron(運氣論) to diagnosis like Maekchin(脈診, a method to diagnose by taking the pulse) and to prescription. 5. Modern society is an era in which it is hard to appreciate the principles of the changes due to the various unusual weather. Therefore, it is necessary to make a new paradigm using Un-gi(運氣) theory, like Hagan(河間) did in Kumwon(金元) period. 6. Unusual weather changes and the geriatric diseases such as cancer and diabetes, may have Sang(象) of Hwayol(火熱) theory at the other side. These diseases have been and will create more serious problems in modern society. As a method to solve these problems. it seems to be very important to understand and apply Hagan's(河間) Hawyol(火熱) theory to modern society.
1. Ounyukki(五運六氣) theory was first developed from observation of astronomical phenomena. Natural phenomena were explained and incorporated into the concepts of Yukki(六氣), and Ohaeng(五行, the concept that all matter in the world are comprised of five fundamental elements), during Chon-guk(戰國) and Han(漢) periods. In that period. Kanji(干支, the method to present time with ten and twelve different kinds of symbol's combinations) was used to record Ounyukki(五運六氣). Theoretical study of Un-gi(運氣, the abbreviation of Ounyukki) was almost completed in Un-gichilpyon(運氣七篇) of Naekyong(內經). Un-gi(運氣) theory was further studied and considered to be very important socially, as well as medically, in Tang(唐), Song(宋), Kum(金), and Won(元) periods. Hagan(河間) published various studies based on Un-gi(運氣) theory in Kum won(金元) periods. 2. Hagan(河間) realized the limitation of a remedy method, of Sanghan(傷寒) theory. Therefore, he made an assumption that the prevalence of diseases in his period are closely related to Hwayol(火熱, a fire and a super-heat; two things out of Yukki(六氣)). His new theory was a result of the study on Kyongjon(經典, bibles of the oriental medicine) and the phenomena of nature. 3. Hagan(河間) used a combination of two basic theories of Pimuripsang(比物立象) and Hanhaesungjeron(亢害承制論) to make understood Hwayol(火熱) theory, Pimuripsang(比物立象) theory explains a method to appreciate the essence of things by comparing Sang(象, an expression of how something appears on the outside) and then making another Sang(象) from the comparison. Hanhaesungjeron(亢害承制論) is a theory to emphasize the importance of a balance of Yukki(六氣). It is that, if one of the elements is exceeded, other thing in the other five elements dominate the exceeded thing to control it for the balance between Yukki(六氣). In addition, he articulated P'yobon(標本. inside and outside of a thing) theory to differentiate the disease symptoms. These theories will help to distinguish real and fake symptoms of diseases, on which Hagan(河間) emphasized its importance. 4. Hagan(河間) published a new theory to explain Ounyukki(五運六氣) theory based on the observation of the nature and the experience from medical practice. And he added Chobyonggi(燥病機, course and rule causing disease in dry conditions) to Pyonggishipkujo(病機十九條, nineteen course and rule causing disease), it strengthened Pyonggi(病機, course and rule causing disease) theories. Moreover. he utilized Un-gi (運氣) theory in a real life situation by applying Un-giron(運氣論) to diagnosis like Maekchin(脈診, a method to diagnose by taking the pulse) and to prescription. 5. Modern society is an era in which it is hard to appreciate the principles of the changes due to the various unusual weather. Therefore, it is necessary to make a new paradigm using Un-gi(運氣) theory, like Hagan(河間) did in Kumwon(金元) period. 6. Unusual weather changes and the geriatric diseases such as cancer and diabetes, may have Sang(象) of Hwayol(火熱) theory at the other side. These diseases have been and will create more serious problems in modern society. As a method to solve these problems. it seems to be very important to understand and apply Hagan's(河間) Hawyol(火熱) theory to modern society.
Kim Sun-Ja;Jeon Ywun-Seok;Lee Seung-Hak;Jeong Byung-Hwan;Lee Myung-Un;Choe Gyu-Ha
The Transactions of the Korean Institute of Power Electronics
/
v.10
no.3
/
pp.257-263
/
2005
Short-circuit rotor windings on a generator causes unstable oscillation of unbalance of flux, asymmetrical heat. In order to prevent serious accidents of short-circuit rotor windings, it is important to study the shorted-turn diagnosis method for rotor windings of the generator. To improve the defects of the diagnosis with sensors, the new sensorless method for rotor shorted-turn diagnosis is proposed, which is to measure the electrical values of the voltage and current at the generator and then to detect if the shorted-turned phenomena would occurred. For the feasibility of the suggested method the theoretical results are shown in the aspects of the air-gap flux density, the flux leakage, the generated output voltage and the shorted field current through the digital simulation. Also the possibility of decision for the suggested sensorless method could be shown in this paper.
It is the common features of the integral reactors that the main components of the RCS are installed within the reactor vessel, and so there are no any flow pipes connecting the coolant pumps or steam generators. Due to no any flow pipes, it is impossible to measure the differential pressure at the RCS of the integral reactors, and it also makes impossible measure the flow-rate of the reactor coolant. As a alternative method, the method by the measurement of coolant pump power has been introduced in this study. Up to now, we did not found out a precedent which the coolant pump power is used for the real-time flow-rate calculation at normal operation of the commercial nuclear power plants. The objective of the study is to embody the real-time flow-rate calculation method by the measurement of coolant pump power in an integral reactor. As a result of the study, we could theoretically reason that the capacity-head curve and capacity-shaft power curve around the rated capacity with the high specific-speeded axial flow pumps have each diagonally steep incline but show the similar shape. Also, we could confirm the above theoretical reasoning from the measured result of the pump motor inputs, So, it has been concluded that it is possible to calculate the real-time flow-rate by the measurement of pump motor inputs. In addition, the compensation for a above new method can be made by HBM being now used in the commercial nuclear power plants.
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