換熱器中英文對(duì)照外文翻譯文獻(xiàn)

1、 中英文對(duì)照外文翻譯(文檔含英文原文和中文翻譯)換熱器的優(yōu)化選型【摘要】板式換熱器的優(yōu)化選型是根據(jù)換熱器的用途和工藝過程中的參數(shù)和NTUKAMCttm，即傳熱單元數(shù) NTU和溫差比（對(duì)數(shù)平均溫差換熱的動(dòng)力）選擇板片形狀、板式換熱器的類型和結(jié)構(gòu)。【關(guān)鍵詞】平均溫差 NTU 板式蒸發(fā)器 冷凝器1 平均溫差tm從公式 QKtmA，tm （tt）dA 中可知，平均溫差tm 是1AA12傳熱的驅(qū)動(dòng)力，對(duì)于各種流動(dòng)形式，如能求出平均溫差，即板面兩側(cè)流體間溫差對(duì)面積的平均值，就能出換熱器的傳熱量。平均溫差是一個(gè)較為直觀的概念，也是評(píng)價(jià)板式換熱器性能的一項(xiàng)重要指標(biāo)。 1.1 對(duì)數(shù)平均溫差的計(jì)算當(dāng)換熱器傳熱量為

2、 dQ，溫度上升為 dt 時(shí)，則 CdQdt，將 C 定義為熱容量，它表示單位時(shí)間通過單位面積交換的熱量，即 dQK（t t ）dAKtdA，hc兩種流體產(chǎn)生的溫度變化分別為 dt dQC ，dt dQC ，dtd（t t ）chhchcdQ（1C 1C ）,則 dA1k（1C 1C ）（dtt），當(dāng)從 Acchh0 積分至 AA 時(shí)，A 1k（1C 1C ）（t t ）（t t ），ci00chhohico由于兩種流體間交換的熱量相等，即 QC （t t ）C （t t ），經(jīng)簡(jiǎn)化后可chhihococi知，QKA （t t ）（t t ）（t t ）（t t ），若ci0hocihicoh

3、ohicot t t ，t t t ，則 QKA （t t ）（t t ）KA 21hico2hoci01120tm，式中的tm（t t ）（t t ）。1122順流 tm（t t ）（t t ） （t t ）（t t ）cihicihocohihoci逆流 tm（t t ）（t t ） （t t ）（t t ）cohicohocihihoci對(duì)于各種流動(dòng)型式，在相同的進(jìn)口、出口溫度條件下，逆流的平均溫差最大。當(dāng)板式換熱器入口和出口兩流體的溫差t 和t 之間的差不大時(shí)，可采21用算術(shù)平均溫差（t t ）2，一般t t 小于 1.5 時(shí)，可采用，若t1122t 為 3 時(shí)，則誤差約為 10%。2

4、1.2 傳熱單元數(shù)法在傳熱單元數(shù)法中引入一個(gè)無量綱參數(shù) NTU，稱為傳熱單元數(shù)，它表示板式換熱器的總熱導(dǎo)（即換熱器傳熱熱阻的倒數(shù)）與流體熱容量的比值 NTUKAMC，它表示相對(duì)于流體熱容流量，該換熱器傳熱能力的大小，即換熱器的無量綱“傳熱能力”。對(duì)于板式換熱器來說，KAMCttm，式中ttm 稱為溫差比，上式中的右邊的工藝過程用 NTUp 表示，左邊的換熱設(shè)備的條件用 NTU 表示。NTUp 是E流體溫度的變化與平均溫差的比值，表示的是用1tm 的變化引起幾度流體溫度變化的值，當(dāng)tm 大時(shí)，NTUp 則??；當(dāng)tm 小時(shí)，它有變大的傾向。相反，在 NTUp變大的過程中，tm 的溫度變化較大，NT

5、Up 較小時(shí)，其tm 的溫度變化較?。ㄒ姳?1）。表 1 tm，NTUp 的關(guān)系 NTUp 大NTUp 小tm 的溫度變化大tm 的溫度變化小板式換熱器的優(yōu)化設(shè)計(jì)計(jì)算，就是在已知溫差比NTU 的條件下，合理地確定其E型號(hào)、流程和傳熱面積，使 NTUp 等于 NTU 。E1.3 換熱過程和 NTU與供熱空調(diào)相關(guān)的換熱過程如下如示： 用蒸汽加熱水 水水換熱a. 蒸汽 133133水 565（生活熱水）c. 一次水 6560二次水 4540（采暖）b. 蒸汽 133133水 5565（采暖）d. 一次水 149二次水 137（制冷）e. 一次水 2924二次水 2621（制冷機(jī)的冷卻）以上 5 例工

6、藝過程的 NTUp（見表 2）表 2 供熱空調(diào)工藝過程的 NTUp（655）94.860.632（6555）72.880.1320.001.44（4540）200.25（137）1.444.17d149 292426211.4 板式換熱器和 NTUENTU 表示板式換熱器的能力，換熱器的面積是具有一定傳熱長度的單位傳熱體E的組合，總傳熱長度是單位長度和流程數(shù)的乘積。當(dāng)NTU 是總數(shù)時(shí)，若每 1 流程數(shù)E為 NTU 時(shí)，則 NTU nNTU （其中 n 是流程數(shù)）。eeE當(dāng) NTU NTU NTUp 時(shí)，換熱器為單程。若 NTU NTUp 時(shí)，則換熱器應(yīng)為多流eeE程，故設(shè)計(jì)時(shí)應(yīng)先預(yù)定 n。由于

7、每種板片單程的 NTU 值基本上是定值，如適合表 2e中 e 的流量為 25m h 的單程板式換熱器的 NTU 為 17 。從NTU AKMC 可知，3ee當(dāng) NTU 為定值時(shí)，AK 成反比，仍以 e 為例，當(dāng) K500kcalh時(shí)，Ae1.672500050083.5 ，流程數(shù) n83.5175。當(dāng) K2500kcalh時(shí)，A16.7 ，流程數(shù) n1。每一流程的 NTU 如下所示：K500，NTU NTU nEee0.33，K2500 時(shí)，NTU 1.67。由此可知，根據(jù)NTU 即可求出換熱器的流程數(shù)，ee傳熱系數(shù)和傳熱面積。從以上可知，若板式換熱器設(shè)計(jì)不合理，可能使換熱面積過大，也可能使板

8、間流速太高，阻力過大。1.5 板式換熱器制造技術(shù)的進(jìn)步，板片種類的增加，提高了板式換熱器對(duì)各種工藝過程的適應(yīng)性。 大 NTU（8），小tm（12）的板式換熱器滿足了區(qū)域供冷和熱泵機(jī)組蒸發(fā)器、冷凝器的要求。從以上分析可知，tm 是換熱的驅(qū)動(dòng)力，若tm 小，即意味著驅(qū)動(dòng)力小，要實(shí)現(xiàn)兩種流體之間的換熱，必須增大傳熱系數(shù)，增大傳熱面積，為了使傳熱面積不至過大，唯一的是增大傳熱系數(shù) K。 淺密波紋板片是北京市京海換熱設(shè)備制造有限責(zé)任公司開發(fā)的新型板片，它的傳熱系數(shù)約為 7000WK，是水平平直波紋板的 2 倍，是人字形波紋板的 1.5 倍，在區(qū)域供冷中時(shí)，檢測(cè)的tm 約為 1.2。在作為冰蓄冷的乙二醇和

9、冷凍水的換熱器使用中，tm 約為 1.5。 板式蒸發(fā)器、板式冷凝器也是北京市京海換熱設(shè)備制造有限責(zé)任公司開發(fā)的適應(yīng)于熱泵機(jī)組的新型換熱器。與管殼式蒸發(fā)器、冷凝器相比，它具有如下優(yōu)點(diǎn)：?jiǎn)?位體積內(nèi)板式蒸發(fā)器、板式冷凝器的傳熱面積約是管殼式換熱器的 3倍；板式蒸發(fā)器的傳熱系數(shù)約為 10001200 WK，板式冷凝器的傳熱系數(shù)約為 15002000WK均為管殼式換熱器的 23倍；在板式蒸發(fā)器上采用了使制冷劑液體分布均勻的分配器裝置，當(dāng)蒸發(fā)器板片數(shù)較多時(shí)，可能會(huì)出現(xiàn)制冷劑液體分配不均的，不能充分利用所有蒸發(fā)傳熱面積，使蒸發(fā)溫度低于設(shè)計(jì)計(jì)算溫度。采用分配器后即能克服上述問題。有關(guān)單位檢測(cè)數(shù)據(jù)說明，板式蒸

10、發(fā)器、板式冷凝器的傳熱系數(shù)在tm 約為 2.53時(shí)，在 15002000 WK 之間，且阻力小，滿足了熱泵機(jī)組的要求。 小 NTU（0.32），大tm（4090）的板式換熱器滿足了熱回收工藝和工藝加熱、冷卻的要求。當(dāng)工藝過程在大tm的條件下進(jìn)行換熱時(shí)，說明驅(qū)動(dòng)力大，所需的傳熱面積較小，對(duì)傳熱系數(shù)要求也不高，但，這種工藝過程或者工作壓力高，或者工作溫度高，或者工藝加熱、冷卻過程的液體中含有纖維或直徑較大的顆粒，對(duì)板式換熱器的承壓、耐溫能力提出了要求，對(duì)換熱器的板間距提出了要求。 排（煙）氣水板殼式換熱器（省能器），排（煙）氣空氣板殼式換熱器（空氣預(yù)熱器）是北京市京海換熱設(shè)備制造有限責(zé)任公司和蘭石

11、化共同開發(fā)出來的新型板式換熱器，全焊接板式換熱器中介質(zhì)的換熱是通過板管束來實(shí)現(xiàn)的，組成板管束的板片由專用模具壓制成型，全焊接式板束裝在壓力殼內(nèi)。波紋板片具有靜攪拌作用，能在很低的雷諾數(shù)下形成湍流，且污垢系數(shù)低，傳熱系數(shù)是管殼式換熱器的 23倍。為了適應(yīng)換熱量大，流體壓降小的要求，板間距大，當(dāng)量直徑約為28。為了滿足工藝的要求板束工作壓力（反壓） P4.5Mpa，板束工作壓力（正壓）同殼體工作壓力，不受限制；工作溫度 t550。烏魯木齊石化分公司 40萬噸年連續(xù)重整采用了進(jìn)料（冷介質(zhì)）和出料（熱介質(zhì)）的板殼式換熱器，進(jìn)料流量 50th，進(jìn)、出口溫渡 88，470。出料流量 50th，進(jìn)、出口溫度

12、 100，500，對(duì)數(shù)平均溫差約 38，總傳熱系數(shù)約為 380kcalh，熱負(fù)荷達(dá) 2310 kcal6h，進(jìn)料壓降 20Kpa，出料壓降 50Kpa。 多效蒸發(fā)板式加熱器（換熱器），這種換熱器既是工藝加熱裝置，又是重要的熱回收裝置。以前由于板式換熱器的流道?。ò彘g距 1.55.0 ），不適宜 于氣氣換熱和蒸氣冷凝；且易堵塞，故不宜用于含懸浮物的流體。為了盡量地發(fā)揮板式換熱器的長處，克服存在問題，適應(yīng)工藝的要求，北京市京海換熱設(shè)備制造有限責(zé)任公司開發(fā)出了新型的多效蒸發(fā)板式換熱器，這種板式換熱器屬寬流道型，其板間距為 8.0 ，適合于蒸氣冷凝，適合于含懸浮物的流體，且不易堵塞，最大處理量達(dá) 12

13、00m h。3 原文New plate heat exchanger optimization SelectionAbstract: The plate heat exchanger Selection is based on the optimization of the use of heatexchangers and in the process of the parameters and NTU = KA / MC = t / tm, that is, transferunits of NTU and the temperature difference than (the aver

14、age temperature difference - Heat transferin power) choose plate shapes, plate heat exchanger and the type of structure.Key words: the average temperature difference between NTU plate evaporator condenser1 average temperature difference tmWhen the heat exchanger to heat-dQ, when the temperature rose

15、 to dt, C = dQ / dt, C will bedefined as heat capacity, it said units of time through the exchange of heat per unit area, dQ = K (th-tc)dA = K tdA, two of the fluid temperature changes were dth =- dQ / Ch, dtc =- dQ / Cc, d t = d(th-tc) = dQ (1/Cc-1/Ch), while dA = 1 / k (1/Cc-1/Ch) (d t / t), when

16、the A = 0 points to A =A0 when, A0 = 1 / k (1/Cc-1 / Ch) (tho-tci) / (thi-tco), because of two fluid exchangebetween the heat equivalent, that is, Q = Ch (thi-tho) = Cc (tco-tci), the simplified Know, Q = KA0(tho-tci) - (thi-tco) / (tho-tci) / (thi-tco), if t1 = thi-tco, t2 = tho-tci , Q = KA0 ( t1-

17、 t2) / ( t1 / t2) = KA0 tm, in- tm = ( t1- t2) / ( t1 / t2) .Down tm = (thi-tci) - (tho-tco) / (thi-tci) / (tho-tci)Countercurrent tm = (thi-tco) - (tho-tci) / (thi-tco) / (tho-tci)For various flow patterns in the same import, export under the conditions of temperature,the average temperature differ

18、ence between the largest counter-current.When the plate heat exchanger import and export of the fluid temperature differencebetween the two t1 and the difference between t2 not available when arithmetic averagetemperature ( t1 + t2) / 2, General t1 / t2 less than 1.5, May be, if t / t2 for 3:00, the

19、error is about 10 percent.1.2 the number of transfer unitsIn the heat transfer unit of the introduction of a few dimensionless parameters NTU, known as the number of transfer units, it said plate heat exchanger of the total thermal conductivity (heatexchanger heat resistance of the countdown) and th

20、e ratio of fluid heat capacity NTU = KA / MC, itsaid in relation to heat fluid flow, heat transfer capacity of the heat exchanger of the size of the heatexchanger that is, non-dimensional heat transfer capability. The plate heat exchanger for, KA / MC= t / tm, where t / tm known as the temperature d

21、ifference than, on the right side of theprocess used NTUp that left the conditions of heat transfer equipment used NTUE said. NTUp is fluidtemperature changes in temperature and the average ratio that is used 1 tm of several changes inthe value of fluid temperature changes, when tm large, NTUp is sm

22、all when tm hours, it hasbecome bigger The tendency. On the contrary, in NTUp larger in the process, tm of the largertemperature changes, NTUp smaller, its tm small changes in temperature (see table 1).Table 1 tm, NTUp relationslargeinintmtemperaturePlate heat exchanger, the optimal design, is known

23、 NTUE temperature difference than theconditions, to determine a reasonable model, processes and heat transfer area, equivalent to NTUpNTUE.1.3 heat transfer process and the NTUHeating and air-conditioning related to the heat transfer process if theshow are as follows: steam heating watera. steam 133

24、 133 Water 5 65 (hot water)b. Steam 133 133 water - water heat exchangerc. a water 65 60 Secondary water 45 40 (heating)d. a water 14 9 Water 55 65 (heating) secondary water 13 7 (refrigeration) e. a water 29 24 Secondary water 26 21 (refrigerator cooling)More than five cases of the process NTUp (se

25、e table 2)Table 2 heating air-conditioning process of NTUpNTUp（655）94.860.632（6555）72.880.13（4540）200.25（137）1.444.17（2621）31.67292426211.4 plate heat exchanger and NTUENTUE plate heat exchanger that the capacity of heat exchanger is the size of a certainlength of the heat and the combination of hea

26、t transfer units, the total length of heat transfer process isthe length and number of units of the product. When the total number of NTUE is, if the number ofprocesses for every 1 NTUe, then NTUE = n NTUe (where n is the number of processes).When NTUe = NTUE = NTUp, the heat exchanger for one-way.

27、If NTUe NTUp, the heatexchanger for many processes, it should be designed to target n. As each plate of one-way NTUevalue is essentially fixed value, such as in e Table 2 for the flow of 25 m3 / h of the one-way NTUeplate heat exchanger for 17 square meters. From NTUe = A K / MC tells us that when N

28、TUe to beon duty, A K is inversely proportional, still e example, when K = 500kcal / h time, A =1.67 25000/500 = 83.5 , the process of n = 83.5/17 5. When K = 2500kcal / h time,A = 16.7 square meters, the flow of n = 1. Each process NTUe as follows: K = 500, NTUe = NTUE / n = 0.33, K = 2500 when, NT

29、Ue = 1.67. So, can be obtained under NTUe the flow of heat exchangers,heat transfer coefficient and heat transfer area. From the above we can see that if the plate heatexchanger design unreasonable and likely to heat transfer area is too large, may also be partitioned sothat flow is too high, too mu

30、ch resistance.1.5 plate heat exchanger manufacturing and technological progress, plate type of increase,raising the plate heat exchanger of the various processes of adaptation. the NTU ( 8), small tm ( 1 2) the plate heat exchanger to meet the districtcooling and heat pump units evaporator, condense

31、r requirements. From the above analysis know, tm is the driving force of heat transfer, if tm small, means that the driver of small, to achieve theheat transfer between the two fluid, we must increase heat transfer coefficient, increasing heat transferarea, in order to Heat to make up too large, is

32、the only increase heat transfer coefficient K. shallow plate of corrugated Beijing, Beijing is the heat transfer equipment manufacturers limitedliability company developed a new type of plate, the heat transfer coefficient of about 7000 W / K, is the level of the flat corrugated board two times, is

33、chevron Corrugated sheets of 1.5 times, in theregional cooling, the detection of tm is about 1.2. As in ice storage of ethylene glycol and chilledwater use in the heat exchanger, tm is about 1.5. plate evaporator, condenser plate Beijing, Beijing is also the heat transfer equipmentmanufacturers limi

34、ted liability companies adapt to the development of a new type of heat pump unitsin the heat exchanger. And the shell-and-evaporator, compared to the condenser, which has thefollowing advantages: unit volume in the evaporator plate, the plate condenser is a heat transfer areaof shell and tube heat e

35、xchanger of three times the plate evaporator heat transfer coefficient About1000 1200 W / K, the condenser plate heat transfer coefficient of about 1500 2000 W / K are shell heat exchanger two to three times the plate on the evaporator used to Refrigerantdistributor of liquid evenly distributed devi

36、ces, when the evaporator plate a few more, may be unevendistribution of liquid refrigerant and can not take full advantage of all the heat and evaporation area,evaporation temperature lower than the calculated design temperature. After a distributor overcomethese problems. Detection of data on the r

37、elevant units, evaporator plate, the plate condenser in the heat transfer coefficient tm about 2.5 3 , in 1500 2000 W / K between the resistanceand small, satisfying the heat pump units Requirements. small NTU ( 0.3 2), the tm ( 40 90 ) of the plate heat exchanger to meetthe heat recovery process an

38、d the process heating and cooling requirements. When the process in the tm conducted under conditions of heat transfer, that driving force, the heat and the smaller, the heattransfer coefficient demand is not high, but that this process or high-pressure work, or work Hightemperature, or process heat

39、ing and cooling process in the liquid containing fiber diameter or largerparticles, the plate heat exchanger, the pressure, temperature and ability to request, the heat exchangerto the plate spacing requirements. Pai (breathing) gas - water shell heat exchanger (Province can), Pai (breathing) gas -

40、shell-air heatexchangers (air preheater) is a heat exchanger in Beijing Beijing-equipment manufacturers limitedliability Portland petrochemical companies and co-developed a new type of plate heat exchanger, allwelded plate heat exchanger in the heat transfer through the medium to achieve the control

41、 board,composed of board control by the plate for forming mold suppression, all-welded - Beam installed inthe pressure shell. Corrugated plate with static mixing, in a very low Reynolds number formed underthe turbulence, and low coefficient of dirt, the heat transfer coefficient is the shell and tube heatexchanger of the two or three times. In order to adapt to the heat transfer, fluid pressure on the request,board space, equivalent diameter of about 28 mm. In order to meet the demands of work pressureplate beam (Anti-pressure) P 4.5 Mpa, the pressure plate