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機械社區
標題:
換熱器的計算---請教
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作者:
baboon9105
時間:
2007-11-30 11:19
標題:
換熱器的計算---請教
最近單位上新的項目，要選擇換熱器，但是如何計算？板式和管式有啥區別？
作者:
olive3000
時間:
2007-12-6 21:25
管式的不好，建議選用板式的。
作者:
hemei
時間:
2008-1-19 13:19
管式的冷卻面積沒有板式冷卻面積大
作者:
天涯125
時間:
2008-2-11 02:54
可以查閱化工版的機械設計手冊第4冊上面有詳細的介紹換熱面積的算法
作者:
13572593532
時間:
2008-2-11 20:23
板式的換熱效率高,不過最好選擇好一些的制造廠家.小的可以用管式的劃算.
作者:
液壓青年
時間:
2008-2-12 09:13
這得看你需要得散熱功率是多大，一般大的用板式散熱器
作者:
開達
時間:
2008-2-15 14:08
COOLER
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SELECTION
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Designation:
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PV = Power loss [kW]
: K0 a" h0 e8 X0 O: Y ?0 d# A% W
P01 = Specific cooling capacity [kW/°C]
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V = Tank contents [l]
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ρoil = Density of the oil [kg/l]
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for mineral oil: 0.915 kg/l
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Coil = Specific heat capacity [kJ/kgK]
: h( l3 N ?8 V6 \" c k
for mineral oil 1.88 kJ/kgK
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∆T = Temperature increase in the
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system [°C]
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t = Operating time [min]
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T1 = Desired oil temperature [°C]
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T3 = Ambient temperature [°C]
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Example 1:
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Measurement of the power loss
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on existing units and machinery.
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For this method the temperature
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increase of the oil is measured
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over a certain period. The power
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loss can be calculated from the
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temperature increase.
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Parameters:
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The oil temperature increases
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from 20 °C to 45 °C over
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15 minutes.
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The tank contains 100 l.
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Heat to be dissipated:
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PV =（∆T × C oil × ρoil × V）/t × 60 [kW]
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PV =25 × 1.88 × 0.915 × 100 / (15 × 60 )
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= 4.78 [kW]
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Cooler selection:
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– Desired oil temperature: 60 °C
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– Ambient temperature air: 30 °C
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P01 =PV / (T1 - T3 ) [kW/°C] =0.159
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A 10% safety margin is
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recommended to allow for
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element contamination, and
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therefore the specific power is:
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P01 × 1.1 = 0.175 kW/°C.
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The power loss 0.175 kW/°C must
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be dissipated by an oil cooler.
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Suggestion:
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–Cooler OK-ELH2 - 3000 rpm,
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P01 = 0.20 kW/°C at 80 l/min
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