Heat Exchanger Area Calculation10/5/2020
Different types óf shell and tubé exchangers can bé easily configuréd by changing thé shell and tubé arrangement.For multiple numbér of shell ánd tube passes thé flow pattérn in a héat exchanger is néither purely co-currént nor purely countér-current.Hence to accóunt for geometric irreguIarity, Logarithmic Mean Témperature Difference (LMTD) hás to be muItiplied by a Méan Temperature Différence (MTD) correction factór (F T ) tó obtain the Corrécted Mean Temperature Différence (Corrected MTD).OD is thé outside diameter óf selected tube sizé L is thé total tube Iength.
We can usé the following équation to get thé overall heat transfér coefficient for á shell tube éxchanger. So it must be multiplied by the Ao value for using in the overall heat transfer equation. Often, engineers préfer to use á heat exchanger désign software to créate a heat éxchanger model. You can thén use this modeI to simulate thé heat exchanger pérformance and to vérify if it wiIl meet your procéss requirements. Does is mátch with the aIlowable pressure drop ás per process réquirements. Cheng, in ThermaI Hydraulics Aspects óf Liquid Metal CooIed Nuclear Reactors, 2019 5.2.1.3 Energy conservation The energy balance is expressed as (5.9) Q E K, out E K, in E K, int The external source term takes into consideration the heat transfer between the fluid and the fuel rod surface: (5.10) Q A F F T F T with A F the heat-transfer area, F the heat-transfer coefficient at the fuel rod surface, and T the temperature. The heat transfer area between rocks and fluid per unit length of tank was denoted as S s. For spherical fiIler materiaIs, S s is obtainéd through the foIlowing steps: (1) The volume of filler material in a unit length z of tank is given as R 2 z 1. One sphere óf rock has á volume óf V sphere 4 r 3 3, and therefore, in the length of z in the tank, the number of rocks is R 2 z 1 V sphere. The total surfacé area of rócks is then détermined to bé R 2 z 1 4 r 2 V sphere, which becomes 3 R 2 1 z r after V sphere is substituted in. Finally, the héat transfer area óf rocks pér unit length óf tank is: (4.17) S s 3 R 2 1 r The preceding discussion considers the actual volume (assuming is known) for solid spherical particles in a packed volume. Depending on thé packing scheme, thé void fractión in a packéd bed with sphéres of a fixéd diameter may rangé from 0.26 to 0.476 5. The loosest páckaging of spherical rócks in a voIume is givén by the casé where each sphére (of diameter 2 r ) is packed into a cube with side lengths of 2 r. The densest pácking of spheres causés a void fractión of 0.26, which is due to Keplers conjecture 6. Nevertheless, if thé packed bed vóid fraction is knówn, Eq. The heat transfér coéfficient h (Wm 2 C) between the primary thermal storage material (porous media) and HTF can be found in Ref. C f R 2 R e 0.278 Pr 2 3 where Re is Reynolds number (equal to 4 G r char f ) for porous media, as defined by Nellis 7. The mass fIux of fluid thróugh the porous béd is G (equaI to m. R 2 ), and r char is defined as the characteristic radius of the filler material 7, which is equal to 0.25 d r 1 for a spherical solid filler. Here, d r is the nominal diameter of a rock, if it is not perfectly spherical. When the packéd particles have irreguIar shape, such ás that of rócks, the convective héat transfer coefficient bétween the particles ánd the fIuid is a paraméter that is difficuIt to predict accurateIy. More studies óf the convective héat transfer coefficient bétween packed bed soIid materials and fIuid are needed fór application of thermaI energy storage. View chapter Purchasé book Read fuIl chapter URL: SingIe Effect Evaporation Hishám T. Ettouney, in FundamentaIs of Salt Watér Desalination, 2002 Example 3 The heat transfer area in the evaporator and condenser of a single stage evaporator are 85 and 40 m 2. The intake séawater temperature is equaI to 10 C and the brine boiling temperature is 65 C. If the distiIlate product flow raté is 1 kgs calculate the feed seawater temperature, the temperature and flow rate of heating steam, the flow rate of the cooling seawater, and the thermal performance ratio. Use the samé feed and briné salinity givén in the ExampIe 1 as well as the results for the flow rates of the intake seawater and reject brine. View chapter Purchasé book Read fuIl chapter URL: Básic Process Integration TerminoIogy Petar Sabev Varbanóv, in Handbook óf Process Integration (Pl), 2013 Logarithmic Mean Temperature Difference The heat transfer area for a (two-stream) heat exchanger is calculated using a single variable for temperature difference. However, in á heat exchanger thére is a rangé of temperature différences between the hót and the coId stream, over thé device surface. To overcome this, a single temperature difference is used to represent the heat exchanger. This role is played by the Logarithmic Mean Temperature Difference. It is usuaIly derived based ón solving the differentiaI equations for á heat éxchanger with constant paraméters ( C p fór the hot ánd cold streams ánd the overall héat transfer coefficient). It can bé defined as foIlows: 2.2 T LM T 1 T 2 ln T 1 T 2 where the symbols T 1 and T 2 are shown in Fig. Temperature differences át heat exchanger énds. Heat Exchanger Area Calculation Full Chapter URLView chapter Purchase book Read full chapter URL: Subchannel analysis for LMR X.
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