Figure P9.34 shows a crossfl ow heat exchanger marketed as a mobile oil cooler. Data provided by the manufacturer for one particular model is as follows: Oil (assume unused engine oil) fl ow rate is...

Figure P9.34 shows a crossfl ow heat exchanger marketed as a mobile oil cooler. Data provided by the manufacturer for one particular model is as follows:

Oil (assume unused engine oil) fl ow rate is 10 gpm.

Air inlet velocity is 1 000 ft /min.

Air inlet area is 15 × 16 in.

Air inlet temperature is 70°F.

Oil inlet temperature is 170°F.

Measured heat-transfer rate is 380 BTU/min.

 a. Determine the UA product for this exchanger.

 b. Calculate the fl uid outlet temperatures.

 Evaluate oil properties at 140°F and air properties at 540°R.

Figure P9.34