• 제목/요약/키워드: Solution flow

검색결과 3,119건 처리시간 0.032초

상용 흡수식 냉동기에서 LiBr 수용액 유량변화에 따른 영향 (Effect of LiBr solution flow rates in commercial absorption chiller)

  • 최승학;정봉철;남임우;정종수;진성민
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2001년도 춘계학술대회논문집D
    • /
    • pp.292-297
    • /
    • 2001
  • This paper discusses the effect of varying LiBr solution circuits flow rates for a direct fired double effect commercial absorption chiller in the parallel flow configuration. The effects of solution flow rates have been investigated for generator, condenser, solution heat exchanger, absorber and evaporator. According to the result of this work, it was found that sensible heat rate of generator increases and refrigerant vapor generated in that decreases when inlet solution flow rate of that increases. As solution flow rate of absorber increases, the degree of superheat increases because of decreasing solution heat exchanger efficiency. The flashing vapor at the top of absorber increases in proportion to the degree of superheat whileas decreases cooling capacity inversely.

  • PDF

LiBr용액량 변화에 따른 수평다관 흡수기의 특성 연구 (An investigation of absorption phenomena in the horizontal staggered tube absorber for various LiBr solution flow rates)

  • 권율;윤상국
    • 설비공학논문집
    • /
    • 제11권3호
    • /
    • pp.332-338
    • /
    • 1999
  • An experimental study of absorption phenomena of water vapor into LiBr solution was carried out to find out the optimum solution flow rate. The staggered bundle of horizontal absorption tubes, which are the same configuration as the commercial heat pump, were tested. The results showed that the heat transfer and absorption rate were enhanced with the increase of LiBr solution flow rate. Those values for different absorber pressures showed the same qualitative trends. The optimum flow rate of solution was obtained as three times of the designed flow rate.

  • PDF

수평 냉각관 외부를 흘러내리는 $LiBr-H_2O$ 수용액의 유동 및 열/물질 전달 특성에 관한 실험적 연구 (An Experimental Study on Flow and Heat / Mass Transfer Characteristics of $LiBr-H_2O$ Solution Flowing over a Cooled Horizontal Tube)

  • 설신수;이상용
    • 대한기계학회논문집B
    • /
    • 제24권8호
    • /
    • pp.1085-1096
    • /
    • 2000
  • An experimental study was performed to examine the heat and mass transfer characteristics of $LiBr-H_2O$ solution flowing over a single horizontal tube with the water vapor absorption. Effects of the flow rate and the temperature of the solution at the top of the tube, the absorber pressure and the drainage pattern were considered. The absorption rate depends highly on the absorber pressure at the low flow rate condition while on the solution inlet temperature at the high flow rate condition. Also, when the flow rate is low, the absorption performance with the sheet flow drainage appeared to be higher than that with the dripping/jet drainage. However, at the high flow rate condition, the case became reversed. The liquid film became wavy with the higher absorption rate. The waves were more probable to form with the lower flow rate and temperature of the solution, and with the higher absorber pressure.

액상 비료를 유도 용액으로 사용하는 정삼투 기반의 해수 담수화 (Forward Osmosis Based Seawater Desalination using Liquid Fertilizer as Draw Solution)

  • 박성직;안희경
    • 한국농공학회논문집
    • /
    • 제55권2호
    • /
    • pp.21-27
    • /
    • 2013
  • The present study explored the way to desalinate seawater for agricultural irrigation using forward osmosis (FO) process using liquid fertilizer as draw solution. FO experiments were performed in a cross flow mode using flat sheet FO membrane. The effect of membrane orientation, flow rate, and draw solution concentration on the performance of forward osmosis was investigated by measuring water flux of forward osmosis membrane. The water flux when the draw solution was placed against the membrane active layer was lower than the water flux when the feed solution was placed against the membrane active layer. This results indicated that the decrease of effective osmotic pressure by dilutive internal concentration polarization was less than that by concentrative internal concentration polarization. Increasing flow rate from 66.7 to 133.1 $cm^3$/min resulted in increase of the water flux when the membrane active layer orient to draw solution and feed solution, respectively. The reduction of resistance to water flow increased water flux at higher flow rate. The water flux of FO membrane increased with increasing draw solution concentration from 10000 to 30000 mg/L. The water flux for $KH_2PO_4$ draw solution was similar to that for commercial fertilizer. Optimization of FO process would contribute to economically desalinate brackish water for agricultural use.

Flow Behavior of Safranine Solution in Prunus sargentii Rehder

  • Hong, Seong-Du;Ahmed, Sheikh Ali;Chun, Su-Kyoung
    • 한국가구학회지
    • /
    • 제18권4호
    • /
    • pp.282-286
    • /
    • 2007
  • An experiment was conducted to compare the 1% safranine solution flow depth in radial and longitudinal direction of Prunus sargentii. Longitudinal flow of safranine solution was found higher than radial flow. Body ray parenchyma was found more permeable than marginal ray parenchyma and it was about 1.3 times higher. Intercellular space conducted safranine solution more than ray parenchyma. Vessel was found to be the main avenue for liquid conduction in longitudinal direction. Different anatomical features of ray, vessel and fiber affected the penetration depth of safranine solution. Moreover initial penetration depth was found to be high and thereafter decreased gradually.

  • PDF

암모니아-물 흡수식 시스템에서 유하액막식 발생기의 해석 (Analysis of Falling-film Generator in Ammonia-water Absorption System)

  • 김병주;손병후;구기갑
    • 설비공학논문집
    • /
    • 제13권5호
    • /
    • pp.422-430
    • /
    • 2001
  • In the present study, an evaporative generation process of ammonia-water solution film on the vertical plate was analysed. For the utilization of waste heat, hot water of low temperature was used as the heat source. The continuity, momentum, energy and diffusion equations for the solution film and vapor mixture were formulated in integral forms and solved numerically. Counter-current solution-vapor flow resulted in the refrigerant vapor of the higher ammonia concentration than that of co-current flow. Eve the rectification of refrigerant vapor was observed near the inlet of solution film in counter-current flow. For the optimum operation of generator using hot water, numerical experiments, based on the heat exchange and generation efficiencies. revealed the inter-relationships among the Reynolds number of the solution film and hot water, and the length of generator. Enhancement of heat and mass transport in the solution film was found to be very effective for the improvement of generation performance, especially at high solution flow rate.

  • PDF

Comparison of the Effects of Pilocarpine Solution and Tablet on Salivary Flow Rate

  • Park, Jo-Eun;Song, Chan-Woo;Kim, Ki-Suk;Kim, Mee-Eun
    • Journal of Oral Medicine and Pain
    • /
    • 제40권1호
    • /
    • pp.10-16
    • /
    • 2015
  • Purpose: Pilocarpine has the effects on improvement of salivary flow and subjective symptoms for xerostomic patients. Because of unwanted side effects following its systemic administration, topical pilocarpine has been paid attention as an alternative. This study aimed to investigate effects of pilocarpine solution as mouthwash on salivary flow and adverse effects compared to systemic administration of 5 mg pilocarpine tablet in healthy subjects. Methods: The study was a double blind, placebo-controlled, crossover clinical trial. Five milligrams pilocarpine tablets, 4 mL of 2% pilocarpine solution and placebo solution were given to 12 healthy volunteers (6 males and 6 females) in a predetermined order with wash-out period of at least two days and unstimulated whole saliva was collected before and after administration of each drug. Blood pressure and pulse rate was also measured and subjective effect and potential side effects were evaluated by a self-administrated questionnaire. Results: Systemic (5 mg tablet) and topical (2% solution) use of pilocarpine significantly increased salivary flow rate in healthy subjects compared to placebo (p<0.001). In both the pilocarpine solution and tablet groups, salivary flow rates at 120 minutes after administration remained increased. Subjective effect on salivation was the largest in the pilocarpine tablet group, followed by the pilocarpine solution group (p<0.05). There was no significant difference in blood pressure and pulse rate after administration of all three drugs. Fewer side effects reported in the pilocarpine solution group than in the tablet group. Conclusions: Two percents pilocarpine solution as mouthwash increases salivary flow rate, definitely superior to placebo solution and comparable to pilocarpine tablet, with fewer side effects in healthy subjects. It indicates a possibility of pilocarpine solution as a useful alternative of pilocarpine tablets for the xerostomic patients with systemic diseases.

Effect of Chemical Passivation Treatment and Flow on the Corrosion of 304 Stainless Steel in Hydrochloric Acid Solution

  • Zhao, Jie;Cheng, Cong Qian;Cao, Tie Shan
    • Corrosion Science and Technology
    • /
    • 제14권6호
    • /
    • pp.273-279
    • /
    • 2015
  • Effects of passive film quality by chemical passivation and solution flow on the corrosion behavior of 304 stainless steel in HCl solution were investigated using a coloration indicator, and by corrosion weight loss, electrochemical polarization and element dissolution measurements. A high redness degree suggests a low passive-film integrity for 304 stainless steel following air exposure, while the minimum redness degree for the samples after chemical passivation suggests a high passive-film integrity. In the static condition, samples subjected to air exposure exhibited a high corrosion rate and preferential dissolution of Fe. Chemical passivation inhibited the corrosion rate due to the intrinsically high structural integrity of the passive film and high concentrations of Cr-rich oxides and hydroxide. Solution flow accelerated corrosion by promoting both the anodic dissolution reaction and the cathodic reaction. Solution flow also altered the preferential dissolution to fast uniform dissolution of metal elements.

A New Concept of Power Flow Analysis

  • Kim, Hyung-Chul;Samann, Nader;Shin, Dong-Geun;Ko, Byeong-Hun;Jang, Gil-Soo;Cha, Jun-Min
    • Journal of Electrical Engineering and Technology
    • /
    • 제2권3호
    • /
    • pp.312-319
    • /
    • 2007
  • The solution of the power flow is one of the most important problems in electrical power systems. These traditional methods such as Gauss-Seidel method and Newton-Raphson (NR) method have had drawbacks up to now such as initial values, abnormal operating solutions and divergences in heavy loads. In order to overcome theses problems, the power flow solution incorporating genetic algorithm (GA) is introduced in this paper. General operator of genetic algorithm, arithmetic crossover, and non-uniform mutation operator of GA are suggested to solve the power flow problem. While abnormal solution cannot be obtained by a NR method, multiple power flow solution can be obtained by a GA method. With a heavy load, both normal solution and abnormal solution can be obtained by a proposed method. In this paper, a floating number representation instead of the binary number representation is introduced for accuracy. Simulation results have been compared with traditional methods.

Carboxymethyl Chitin 수용액의 임계농도와 유동방정식 (The Critical Concentration and Flow Equation of Aqueous Carboxymethyl Chitin Solution)

  • 박성민;이근태;김상무
    • 한국수산과학회지
    • /
    • 제29권1호
    • /
    • pp.92-96
    • /
    • 1996
  • CM-chitin의 고유특성 및 유동특성을 밝혀 효과적으로 식품산업에 이용하기 위하여 CM-chitin 수용액의 유동특성 중 임계농도와 유동방정식을 조사하였다. 물에서 CM-chitin의 환원농도는 2.5이었으며, 이 때의 임계농도는 $0.8\%(w/v)$이었다. 즉 $0.8\%$ 이하의 농도에서는 분자사슬간 상호작용이 일어나지 않았으며, $0.8\%$ 이상에서 상호작용이 일어나는 것으로 나타났다. $0.5\%$ CM-chitin 용액은 전단속도가 증가하여도 점도는 일정하게 유지되는 뉴우튼 유체의 특성을 보였으며, $1.0\%$ 용액은 전단속도가 증가하면 점도가 낮아지는 의가소성 유체의 특성을 보였다. $3.0\%$ CM-chitin 수용액의 유동상수 $\eta_\infty,\;\eta_0,\;\beta$, n은 각각 $0.0908(\fallingdotseq0.1)cp$, 770cp, 0.81, 0.36이었다. 따라서 $3.0\%$ CM-chitin 수용액의 유동방정식은 $\eta=0.1+\{{770/(1+0.81D^{0.36})\}$으로 나타낼 수 있다.

  • PDF